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2016PhRvL.116f1102A

Observation of Gravitational Waves from a Binary Black Hole Merger

2016-01-01

['-', '-']

[]

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0 ×10<SUP>-21</SUP>. It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203 000 years, equivalent to a significance greater than 5.1 σ . The source lies at a luminosity distance of 41 0<SUB>-180</SUB><SUP>+160</SUP> Mpc corresponding to a redshift z =0.0 9<SUB>-0.04</SUB><SUP>+0.03</SUP> . In the source frame, the initial black hole masses are 3 6<SUB>-4</SUB><SUP>+5</SUP>M<SUB>⊙</SUB> and 2 9<SUB>-4</SUB><SUP>+4</SUP>M<SUB>⊙</SUB> , and the final black hole mass is 6 2<SUB>-4</SUB><SUP>+4</SUP>M<SUB>⊙</SUB> , with 3. 0<SUB>-0.5</SUB><SUP>+0.5</SUP>M<SUB>⊙</SUB> c<SUP>2</SUP> radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

[]

https://arxiv.org/pdf/1602.03837.pdf

2000ApJ...539L...9F

A Fundamental Relation between Supermassive Black Holes and Their Host Galaxies

2000-01-01

['black hole physics', 'galaxies evolution', 'galaxies kinematics and dynamics', 'astrophysics']

[]

The masses of supermassive black holes correlate almost perfectly with the velocity dispersions of their host bulges, M<SUB>bh</SUB>~σ<SUP>α</SUP>, where α=4.8+/-0.5. The relation is much tighter than the relation between M<SUB>bh</SUB> and bulge luminosity, with a scatter no larger than expected on the basis of measurement error alone. Black hole masses recently estimated by Magorrian et al. lie systematically above the M<SUB>bh</SUB>-σ relation defined by more accurate mass estimates, some by as much as 2 orders of magnitude. The tightness of the M<SUB>bh</SUB>-σ relation implies a strong link between black hole formation and the properties of the stellar bulge.

[]

https://arxiv.org/pdf/astro-ph/0006053.pdf

2000ApJ...539L..13G

A Relationship between Nuclear Black Hole Mass and Galaxy Velocity Dispersion

2000-01-01

['galaxies general', 'galaxies nuclei', 'galaxies statistics', 'astrophysics']

[]

We describe a correlation between the mass M<SUB>bh</SUB> of a galaxy's central black hole and the luminosity-weighted line-of-sight velocity dispersion σ<SUB>e</SUB> within the half-light radius. The result is based on a sample of 26 galaxies, including 13 galaxies with new determinations of black hole masses from Hubble Space Telescope measurements of stellar kinematics. The best-fit correlation is M<SUB>bh</SUB>=1.2(+/-0.2)×10<SUP>8</SUP> M<SUB>solar</SUB>(σ<SUB>e</SUB>/200 km s<SUP>-1</SUP>)<SUP>3.75 (+/-0.3)</SUP> over almost 3 orders of magnitude in M<SUB>bh</SUB>; the scatter in M<SUB>bh</SUB> at fixed σ<SUB>e</SUB> is only 0.30 dex, and most of this is due to observational errors. The M<SUB>bh</SUB>-σ<SUB>e</SUB> relation is of interest not only for its strong predictive power but also because it implies that central black hole mass is constrained by and closely related to properties of the host galaxy's bulge.

[]

https://arxiv.org/pdf/astro-ph/0006289.pdf

2013ARA&A..51..511K

Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies

2013-01-01

['-']

[]

Supermassive black holes (BHs) have been found in 85 galaxies by dynamical modeling of spatially resolved kinematics. The Hubble Space Telescope revolutionized BH research by advancing the subject from its proof-of-concept phase into quantitative studies of BH demographics. Most influential was the discovery of a tight correlation between BH mass [Formula: see text] and the velocity dispersion σ of the bulge component of the host galaxy. Together with similar correlations with bulge luminosity and mass, this led to the widespread belief that BHs and bulges coevolve by regulating each other's growth. Conclusions based on one set of correlations from [Formula: see text] in brightest cluster ellipticals to [Formula: see text] in the smallest galaxies dominated BH work for more than a decade. New results are now replacing this simple story with a richer and more plausible picture in which BHs correlate differently with different galaxy components. A reasonable aim is to use this progress to refine our understanding of BH-galaxy coevolution. BHs with masses of 10<SUP>5</SUP>-10<SUP>6</SUP>M<SUB>⊙</SUB> are found in many bulgeless galaxies. Therefore, classical (elliptical-galaxy-like) bulges are not necessary for BH formation. On the other hand, although they live in galaxy disks, BHs do not correlate with galaxy disks. Also, any [Formula: see text] correlations with the properties of disk-grown pseudobulges and dark matter halos are weak enough to imply no close coevolution. The above and other correlations of host-galaxy parameters with each other and with [Formula: see text] suggest that there are four regimes of BH feedback. (1) Local, secular, episodic, and stochastic feeding of small BHs in largely bulgeless galaxies involves too little energy to result in coevolution. (2) Global feeding in major, wet galaxy mergers rapidly grows giant BHs in short-duration, quasar-like events whose energy feedback does affect galaxy evolution. The resulting hosts are classical bulges and coreless-rotating-disky ellipticals. (3) After these AGN phases and at the highest galaxy masses, maintenance-mode BH feedback into X-ray-emitting gas has the primarily negative effect of helping to keep baryons locked up in hot gas and thereby keeping galaxy formation from going to completion. This happens in giant, core-nonrotating-boxy ellipticals. Their properties, including their tight correlations between [Formula: see text] and core parameters, support the conclusion that core ellipticals form by dissipationless major mergers. They inherit coevolution effects from smaller progenitor galaxies. Also, (4) independent of any feedback physics, in BH growth modes 2 and 3, the averaging that results from successive mergers plays a major role in decreasing the scatter in [Formula: see text] correlations from the large values observed in bulgeless and pseudobulge galaxies to the small values observed in giant elliptical galaxies.

[]

https://arxiv.org/pdf/1304.7762.pdf

2006MNRAS.365...11C

The many lives of active galactic nuclei: cooling flows, black holes and the luminosities and colours of galaxies

2006-01-01

['black hole physics', 'galaxies active', 'hydrodynamics', 'galaxies evolution', 'galaxies formation', 'cosmology theory', 'astrophysics']

[]

We simulate the growth of galaxies and their central supermassive black holes by implementing a suite of semi-analytic models on the output of the Millennium Run, a very large simulation of the concordance Λ cold dark matter cosmogony. Our procedures follow the detailed assembly history of each object and are able to track the evolution of all galaxies more massive than the Small Magellanic Cloud throughout a volume comparable to that of large modern redshift surveys. In this first paper we supplement previous treatments of the growth and activity of central black holes with a new model for `radio' feedback from those active galactic nuclei that lie at the centre of a quasi-static X-ray-emitting atmosphere in a galaxy group or cluster. We show that for energetically and observationally plausible parameters such a model can simultaneously explain: (i) the low observed mass drop-out rate in cooling flows; (ii) the exponential cut-off at the bright end of the galaxy luminosity function; and (iii) the fact that the most massive galaxies tend to be bulge-dominated systems in clusters and to contain systematically older stars than lower mass galaxies. This success occurs because static hot atmospheres form only in the most massive structures, and radio feedback (in contrast, for example, to supernova or starburst feedback) can suppress further cooling and star formation without itself requiring star formation. We discuss possible physical models that might explain the accretion rate scalings required for our phenomenological `radio mode' model to be successful.

[]

https://arxiv.org/pdf/astro-ph/0508046.pdf

1992PhRvL..69.1849B

Black hole in three-dimensional spacetime

1992-01-01

['black hole physics', 'cosmology miscellaneous', 'relativity', 'thermodynamics', 'electrodynamics', 'relativity', 'theory', 'quantum theory', 'thermodynamics', '-', '-', '-', '-', 'black hole physics', '-']

[]

The standard Einstein-Maxwell equations in 2+1 spacetime dimensions, with a negative cosmological constant, admit a black hole solution. The 2+1 black hole-characterized by mass, angular momentum, and charge, defined by flux integrals at infinity-is quite similar to its 3+1 counterpart. Anti-de Sitter space appears as a negative energy state separated by a mass gap from the continuous black hole spectrum. Evaluation of the partition function yields that the entropy is equal to twice the perimeter length of the horizon.

[]

https://arxiv.org/pdf/hep-th/9204099.pdf

2019ApJ...875L...1E

First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole

2019-01-01

['accretion', 'accretion disks', 'black hole physics', 'galaxies active', 'galaxies', 'galaxies jets', 'gravitation', '-', '-', '-']

[]

When surrounded by a transparent emission region, black holes are expected to reveal a dark shadow caused by gravitational light bending and photon capture at the event horizon. To image and study this phenomenon, we have assembled the Event Horizon Telescope, a global very long baseline interferometry array observing at a wavelength of 1.3 mm. This allows us to reconstruct event-horizon-scale images of the supermassive black hole candidate in the center of the giant elliptical galaxy M87. We have resolved the central compact radio source as an asymmetric bright emission ring with a diameter of 42 ± 3 μas, which is circular and encompasses a central depression in brightness with a flux ratio ≳10:1. The emission ring is recovered using different calibration and imaging schemes, with its diameter and width remaining stable over four different observations carried out in different days. Overall, the observed image is consistent with expectations for the shadow of a Kerr black hole as predicted by general relativity. The asymmetry in brightness in the ring can be explained in terms of relativistic beaming of the emission from a plasma rotating close to the speed of light around a black hole. We compare our images to an extensive library of ray-traced general-relativistic magnetohydrodynamic simulations of black holes and derive a central mass of M = (6.5 ± 0.7) × 10<SUP>9</SUP> M <SUB>⊙</SUB>. Our radio-wave observations thus provide powerful evidence for the presence of supermassive black holes in centers of galaxies and as the central engines of active galactic nuclei. They also present a new tool to explore gravity in its most extreme limit and on a mass scale that was so far not accessible.

[]

https://arxiv.org/pdf/1906.11238.pdf

2016PhRvL.116x1103A

GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole Coalescence

2016-01-01

['-', '-']

[]

We report the observation of a gravitational-wave signal produced by the coalescence of two stellar-mass black holes. The signal, GW151226, was observed by the twin detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) on December 26, 2015 at 03:38:53 UTC. The signal was initially identified within 70 s by an online matched-filter search targeting binary coalescences. Subsequent off-line analyses recovered GW151226 with a network signal-to-noise ratio of 13 and a significance greater than 5 σ . The signal persisted in the LIGO frequency band for approximately 1 s, increasing in frequency and amplitude over about 55 cycles from 35 to 450 Hz, and reached a peak gravitational strain of 3. 4<SUB>-0.9</SUB><SUP>+0.7</SUP>×10<SUP>-22</SUP> . The inferred source-frame initial black hole masses are 14.2<SUB>-3.7</SUB><SUP>+8.3</SUP> M<SUB>⊙</SUB> and 7. 5<SUB>-2.3</SUB><SUP>+2.3</SUP> M<SUB>⊙</SUB>, and the final black hole mass is 20.8<SUB>-1.7</SUB><SUP>+6.1</SUP> M<SUB>⊙</SUB>. We find that at least one of the component black holes has spin greater than 0.2. This source is located at a luminosity distance of 44 0<SUB>-190</SUB><SUP>+180</SUP> Mpc corresponding to a redshift of 0.0 9<SUB>-0.04</SUB><SUP>+0.03</SUP>. All uncertainties define a 90% credible interval. This second gravitational-wave observation provides improved constraints on stellar populations and on deviations from general relativity.

[]

https://arxiv.org/pdf/1606.04855.pdf

2005Natur.433..604D

Energy input from quasars regulates the growth and activity of black holes and their host galaxies

2005-01-01

['astrophysics']

[]

In the early Universe, while galaxies were still forming, black holes as massive as a billion solar masses powered quasars. Supermassive black holes are found at the centres of most galaxies today, where their masses are related to the velocity dispersions of stars in their host galaxies and hence to the mass of the central bulge of the galaxy. This suggests a link between the growth of the black holes and their host galaxies, which has indeed been assumed for a number of years. But the origin of the observed relation between black hole mass and stellar velocity dispersion, and its connection with the evolution of galaxies, have remained unclear. Here we report simulations that simultaneously follow star formation and the growth of black holes during galaxy-galaxy collisions. We find that, in addition to generating a burst of star formation, a merger leads to strong inflows that feed gas to the supermassive black hole and thereby power the quasar. The energy released by the quasar expels enough gas to quench both star formation and further black hole growth. This determines the lifetime of the quasar phase (approaching 100million years) and explains the relationship between the black hole mass and the stellar velocity dispersion.

[]

https://arxiv.org/pdf/astro-ph/0502199.pdf

2005PhRvL..94k1601K

Viscosity in Strongly Interacting Quantum Field Theories from Black Hole Physics

2005-01-01

['-', '-', '-', '-', '-', '-', '-', 'relativity', '-', '-', '-']

[]

The ratio of shear viscosity to volume density of entropy can be used to characterize how close a given fluid is to being perfect. Using string theory methods, we show that this ratio is equal to a universal value of ℏ/4πk<SUB>B</SUB> for a large class of strongly interacting quantum field theories whose dual description involves black holes in anti de Sitter space. We provide evidence that this value may serve as a lower bound for a wide class of systems, thus suggesting that black hole horizons are dual to the most ideal fluids.

[]

https://arxiv.org/pdf/hep-th/0405231.pdf

2002ApJ...574..740T

The Slope of the Black Hole Mass versus Velocity Dispersion Correlation

2002-01-01

['black hole physics', 'galaxies bulges', 'galaxies fundamental parameters', 'galaxies nuclei', 'galaxy bulge', 'galaxy kinematics and dynamics', 'astrophysics']

[]

Observations of nearby galaxies reveal a strong correlation between the mass of the central dark object M<SUB>BH</SUB> and the velocity dispersion σ of the host galaxy, of the form log(M<SUB>BH</SUB>/M<SUB>solar</SUB>)=α+βlog(σ/ σ<SUB>0</SUB>) however, published estimates of the slope β span a wide range (3.75-5.3). Merritt &amp; Ferrarese have argued that low slopes (&lt;~4) arise because of neglect of random measurement errors in the dispersions and an incorrect choice for the dispersion of the Milky Way Galaxy. We show that these explanations and several others account for at most a small part of the slope range. Instead, the range of slopes arises mostly because of systematic differences in the velocity dispersions used by different groups for the same galaxies. The origin of these differences remains unclear, but we suggest that one significant component of the difference results from Ferrarese &amp; Merritt's extrapolation of central velocity dispersions to r<SUB>e</SUB>/8 (r<SUB>e</SUB> is the effective radius) using an empirical formula. Another component may arise from dispersion-dependent systematic errors in the measurements. A new determination of the slope using 31 galaxies yields β=4.02+/-0.32, α=8.13+/-0.06 for σ<SUB>0</SUB>=200 km s<SUP>-1</SUP>. The M<SUB>BH</SUB>-σ relation has an intrinsic dispersion in logM<SUB>BH</SUB> that is no larger than 0.25-0.3 dex and may be smaller if observational errors have been underestimated. In an appendix, we present a simple kinematic model for the velocity-dispersion profile of the Galactic bulge.

[]

https://arxiv.org/pdf/astro-ph/0203468.pdf

2017PhRvL.118v1101A

GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2

2017-01-01

['-', '-']

[]

We describe the observation of GW170104, a gravitational-wave signal produced by the coalescence of a pair of stellar-mass black holes. The signal was measured on January 4, 2017 at 10∶11:58.6 UTC by the twin advanced detectors of the Laser Interferometer Gravitational-Wave Observatory during their second observing run, with a network signal-to-noise ratio of 13 and a false alarm rate less than 1 in 70 000 years. The inferred component black hole masses are 31. 2<SUB>-6.0</SUB><SUP>+8.4</SUP>M<SUB>⊙</SUB> and 19. 4<SUB>-5.9</SUB><SUP>+5.3</SUP> M<SUB>⊙</SUB> (at the 90% credible level). The black hole spins are best constrained through measurement of the effective inspiral spin parameter, a mass-weighted combination of the spin components perpendicular to the orbital plane, χ<SUB>eff</SUB>=-0.1 2<SUB>-0.30</SUB><SUP>+0.21</SUP> . This result implies that spin configurations with both component spins positively aligned with the orbital angular momentum are disfavored. The source luminosity distance is 88 0<SUB>-390</SUB><SUP>+450</SUP> Mpc corresponding to a redshift of z =0.1 8<SUB>-0.07</SUB><SUP>+0.08</SUP> . We constrain the magnitude of modifications to the gravitational-wave dispersion relation and perform null tests of general relativity. Assuming that gravitons are dispersed in vacuum like massive particles, we bound the graviton mass to m<SUB>g</SUB>≤7.7 ×10<SUP>-23</SUP> eV /c<SUP>2</SUP> . In all cases, we find that GW170104 is consistent with general relativity.

[]

https://arxiv.org/pdf/1706.01812.pdf

1993PhRvD..48.3427W

Black hole entropy is Noether charge

1993-01-01

['-', '-', '-', 'black hole physics', '-']

[]

We consider a general, classical theory of gravity in n dimensions, arising from a diffeomorphism-invariant Lagrangian. In any such theory, to each vector field ξ<SUP>a</SUP> on spacetime one can associate a local symmetry and, hence, a Noether current (n-1)-form j and (for solutions to the field equations) a Noether charge (n-2)-form Q-both of which are locally constructed from ξ<SUP>a</SUP> and the fields appearing in the Lagrangian. Assuming only that the theory admits stationary black hole solutions with a bifurcate Killing horizon (with bifurcation surface Σ), and that the canonical mass and angular momentum of solutions are well defined at infinity, we show that the first law of black hole mechanics always holds for perturbations to nearby stationary black hole solutions. The quantity playing the role of black hole entropy in this formula is simply 2π times the integral over Σ of the Noether charge (n-2)-form associated with the horizon Killing field. Furthermore, we show that this black hole entropy always is given by a local geometrical expression on the horizon of the black hole. We thereby obtain a natural candidate for the entropy of a dynamical black hole in a general theory of gravity. Our results show that the validity of the ``second law'' of black hole mechanics in dynamical evolution from an initially stationary black hole to a final stationary state is equivalent to the positivity of a total Noether flux, and thus may be intimately related to the positive energy properties of the theory. The relationship between the derivation of our formula for black hole entropy and the derivation via ``Euclidean methods'' also is explained.

[]

https://arxiv.org/pdf/gr-qc/9307038.pdf

2014NatCo...5.4475Q

High-mobility transport anisotropy and linear dichroism in few-layer black phosphorus

2014-01-01

['-', '-']

[]

Two-dimensional crystals are emerging materials for nanoelectronics. Development of the field requires candidate systems with both a high carrier mobility and, in contrast to graphene, a sufficiently large electronic bandgap. Here we present a detailed theoretical investigation of the atomic and electronic structure of few-layer black phosphorus (BP) to predict its electrical and optical properties. This system has a direct bandgap, tunable from 1.51 eV for a monolayer to 0.59 eV for a five-layer sample. We predict that the mobilities are hole-dominated, rather high and highly anisotropic. The monolayer is exceptional in having an extremely high hole mobility (of order 10,000 cm<SUP>2</SUP> V<SUP>-1</SUP> s<SUP>-1</SUP>) and anomalous elastic properties which reverse the anisotropy. Light absorption spectra indicate linear dichroism between perpendicular in-plane directions, which allows optical determination of the crystalline orientation and optical activation of the anisotropic transport properties. These results make few-layer BP a promising candidate for future electronics.

[]

https://arxiv.org/pdf/1401.5045.pdf

2006ARA&A..44...49R

X-Ray Properties of Black-Hole Binaries

2006-01-01

['astrophysics']

[]

We review the properties and behavior of 20 X-ray binaries that contain a dynamically-confirmed black hole, 17 of which are transient systems. During the past decade, many of these transient sources were observed daily throughout the course of their typically year-long outburst cycles using the large-area timing detector aboard the Rossi X-Ray Timing Explorer. The evolution of these transient sources is complex. Nevertheless, there are behavior patterns common to all of them as we show in a comprehensive comparison of six selected systems. Central to this comparison are three X-ray states of accretion, which are reviewed and defined quantitatively. We discuss phenomena that arise in strong gravitational fields, including relativistically-broadened Fe lines, high-frequency quasi-periodic oscillations (100 450 Hz), and relativistic radio and X-ray jets. Such phenomena show us how a black hole interacts with its environment, thereby complementing the picture of black holes that gravitational wave detectors will provide. We sketch a scenario for the potential impact of timing/spectral studies of accreting black holes on physics and discuss a current frontier topic, namely, the measurement of black hole spin.

[]

https://arxiv.org/pdf/astro-ph/0606352.pdf

2005MNRAS.361..776S

Modelling feedback from stars and black holes in galaxy mergers

2005-01-01

['methods numerical', 'galaxies active', 'galaxies interactions', 'galaxies starburst', 'galaxies structure', 'astrophysics']

[]

We describe techniques for incorporating feedback from star formation and black hole (BH) accretion into simulations of isolated and merging galaxies. At present, the details of these processes cannot be resolved in simulations on galactic scales. Our basic approach therefore involves forming coarse-grained representations of the properties of the interstellar medium (ISM) and BH accretion starting from basic physical assumptions, so that the impact of these effects can be included on resolved scales. We illustrate our method using a multiphase description of star-forming gas. Feedback from star formation pressurizes highly overdense gas, altering its effective equation of state (EOS). We show that this allows the construction of stable galaxy models with much larger gas fractions than possible in earlier numerical work. We extend the model by including a treatment of gas accretion onto central supermassive BHs in galaxies. Assuming thermal coupling of a small fraction of the bolometric luminosity of accreting BHs to the surrounding gas, we show how this feedback regulates the growth of BHs. In gas-rich mergers of galaxies, we observe a complex interplay between starbursts and central active galactic nuclei (AGN) activity when the tidal interaction triggers intense nuclear inflows of gas. Once an accreting supermassive BH has grown to a critical size, feedback terminates its further growth and expels gas from the central region in a powerful quasar-driven wind. Our simulation methodology is therefore able to address the coupled processes of gas dynamics, star formation and BH accretion during the formation of galaxies.

[]

https://arxiv.org/pdf/astro-ph/0411108.pdf

1994PhRvD..50..846I

Some properties of the Noether charge and a proposal for dynamical black hole entropy

1994-01-01

['-', '-', '-', 'black hole physics', '-']

[]

We consider a general, classical theory of gravity with arbitrary matter fields in n dimensions, arising from a diffeomorphism-invariant Lagrangian L. We first show that L alwasy can be written in a ``manifestly covariant'' form. We then show that the symplectic potential current (n-1)-form FTHETA and the symplectic current (n-1)-form ω for the theory always can be globally defined in a covariant manner. Associated with any infinitesimal diffeomorphism is a Noether current (n-1)-form J and corresponding Noether charge (n-2)-form Q. We derive a general ``decomposition formula'' for Q. Using this formula for the Noether charge, we prove that the first law of black hole mechanics holds for arbitrary perturbations of a stationary black hole. (For higher derivative theories, previous arguments had established this law only for stationary perturbations.) Finally, we propose a local, geometrical prescription for the entropy S<SUB>dyn</SUB> of a dynamical black hole. This prescription agrees with the Noether charge formula for stationary black holes and their perturbations, and is independent of all ambiguities associated with the choices of L, FTHETA, and Q. However, the issue of whether this dynamical entropy in general obeys a ``second law'' of black hole mechanics remains open. In an appendix, we apply some of our results to theories with a nondynamical metric and also briefly develop the theory of stress-energy pseudotensors.

[]

https://arxiv.org/pdf/gr-qc/9403028.pdf

2017PhRvL.119n1101A

GW170814: A Three-Detector Observation of Gravitational Waves from a Binary Black Hole Coalescence

2017-01-01

['-', '-', '-']

[]

On August 14, 2017 at 10∶30:43 UTC, the Advanced Virgo detector and the two Advanced LIGO detectors coherently observed a transient gravitational-wave signal produced by the coalescence of two stellar mass black holes, with a false-alarm rate of <inline-formula><mml:math display="inline"><mml:mo>≲</mml:mo><mml:mn>1</mml:mn></mml:math></inline-formula> in 27 000 years. The signal was observed with a three-detector network matched-filter signal-to-noise ratio of 18. The inferred masses of the initial black holes are <inline-formula><mml:math display="inline"><mml:mrow><mml:mn>30.</mml:mn><mml:msubsup><mml:mrow><mml:mn>5</mml:mn></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>3.0</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>5.7</mml:mn></mml:mrow></mml:msubsup><mml:msub><mml:mrow><mml:mi>M</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">⊙</mml:mo></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula> and <inline-formula><mml:math display="inline"><mml:mn>25</mml:mn><mml:mo>.</mml:mo><mml:msubsup><mml:mn>3</mml:mn><mml:mrow><mml:mo>-</mml:mo><mml:mn>4.2</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>2.8</mml:mn></mml:mrow></mml:msubsup><mml:msub><mml:mrow><mml:mi>M</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">⊙</mml:mo></mml:mrow></mml:msub></mml:math></inline-formula> (at the 90% credible level). The luminosity distance of the source is <inline-formula><mml:math display="inline"><mml:mrow><mml:mn>54</mml:mn><mml:msubsup><mml:mrow><mml:mn>0</mml:mn></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>210</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>130</mml:mn></mml:mrow></mml:msubsup><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>Mpc</mml:mi></mml:mrow></mml:math></inline-formula>, corresponding to a redshift of <inline-formula><mml:math display="inline"><mml:mi>z</mml:mi><mml:mo>=</mml:mo><mml:mn>0.1</mml:mn><mml:msubsup><mml:mn>1</mml:mn><mml:mrow><mml:mo>-</mml:mo><mml:mn>0.04</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.03</mml:mn></mml:mrow></mml:msubsup></mml:math></inline-formula>. A network of three detectors improves the sky localization of the source, reducing the area of the 90% credible region from <inline-formula><mml:math display="inline"><mml:mrow><mml:mn>1160</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mrow><mml:msup><mml:mrow><mml:mi>deg</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:mrow></mml:math></inline-formula> using only the two LIGO detectors to <inline-formula><mml:math display="inline"><mml:mrow><mml:mn>60</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mrow><mml:msup><mml:mrow><mml:mi>deg</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:mrow></mml:math></inline-formula> using all three detectors. For the first time, we can test the nature of gravitational-wave polarizations from the antenna response of the LIGO-Virgo network, thus enabling a new class of phenomenological tests of gravity.

[]

https://arxiv.org/pdf/1709.09660.pdf

2009CQGra..26p3001B

TOPICAL REVIEW: Quasinormal modes of black holes and black branes

2009-01-01

['-', '-', '-', '-']

[]

Quasinormal modes are eigenmodes of dissipative systems. Perturbations of classical gravitational backgrounds involving black holes or branes naturally lead to quasinormal modes. The analysis and classification of the quasinormal spectra require solving non-Hermitian eigenvalue problems for the associated linear differential equations. Within the recently developed gauge-gravity duality, these modes serve as an important tool for determining the near-equilibrium properties of strongly coupled quantum field theories, in particular their transport coefficients, such as viscosity, conductivity and diffusion constants. In astrophysics, the detection of quasinormal modes in gravitational wave experiments would allow precise measurements of the mass and spin of black holes as well as new tests of general relativity. This review is meant as an introduction to the subject, with a focus on the recent developments in the field.

[]

https://arxiv.org/pdf/0905.2975.pdf

2006ApJS..163....1H

A Unified, Merger-driven Model of the Origin of Starbursts, Quasars, the Cosmic X-Ray Background, Supermassive Black Holes, and Galaxy Spheroids

2006-01-01

['cosmology theory', 'galaxies active', 'galaxies evolution', 'galaxies nuclei', 'galaxies quasars', 'astrophysics']

[]

We present an evolutionary model for starbursts, quasars, and spheroidal galaxies in which mergers between gas-rich galaxies drive nuclear inflows of gas, producing starbursts and feeding the buried growth of supermassive black holes (BHs) until feedback expels gas and renders a briefly visible optical quasar. The quasar lifetime and obscuring column density depend on both the instantaneous and peak quasar luminosity, and we determine this dependence using a large set of galaxy merger simulations varying galaxy properties, orbital geometry, and gas physics. We use these fits to deconvolve observed quasar luminosity functions and obtain the evolution of the formation rate of quasars with peak luminosity, n dot(L<SUB>peak</SUB>,z). Quasars spend extended periods at luminosities well below peak, so n dot(L<SUB>peak</SUB>) has a maximum corresponding to the ``break'' in the observed luminosity function. From n dot(L<SUB>peak</SUB>) and our simulations, we obtain self-consistent hard and soft X-ray and optical luminosity functions and predict many observables at multiple redshifts, including column density distributions of optical and X-ray samples, the luminosity function of broad-line quasars in X-ray samples and broad-line fraction versus luminosity, active BH mass functions, the distribution of Eddington ratios, the mass function of relic BHs and total BH mass density, and the cosmic X-ray background. In every case, our predictions agree well with observed estimates, without invoking ad hoc assumptions about source properties or distributions. We provide a library of Monte Carlo realizations of our models for comparison with observations.

[]

https://arxiv.org/pdf/astro-ph/0506398.pdf

1993PhRvD..48.1506B

Geometry of the 2+1 black hole

1993-01-01

['-', '-', 'black hole physics', '-', '-']

[]

The geometry of the spinning black holes of standard Einstein theory in 2+1 dimensions, with a negative cosmological constant, and without couplings to matter, is analyzed in detail. It is shown that the black hole arises from identifications of points of anti-de Sitter space by a discrete subgroup of SO(2,2). The generic black hole is a smooth manifold in the metric sense. The surface r=0 is not a curvature singularity but, rather, a singularity in the causal structure. Continuing past it would introduce closed timelike lines. However, simple examples show the regularity of the metric at r=0 to be unstable: couplings to matter bring in a curvature singularity there. Kruskal coordinates and Penrose diagrams are exhibited. Special attention is given to the limiting cases of (i) the spinless hole of zero mass, which differs from anti-de Sitter space and plays the role of the vacuum, and (ii) the spinning hole of maximal angular momentum. A thorough classification of the elements of the Lie algebra of SO(2,2) is given in an appendix.

[]

https://arxiv.org/pdf/gr-qc/9302012.pdf

1999LRR.....2....2K

Quasi-Normal Modes of Stars and Black Holes

1999-01-01

['-', '-', 'gravitational waves', '-', 'neutron', '-', 'astrophysics']

[]

Perturbations of stars and black holes have been one of the main topics of relativistic astrophysics for the last few decades. They are of particular importance today, because of their relevance to gravitational wave astronomy. In this review we present the theory of quasi-normal modes of compact objects from both the mathematical and astrophysical points of view. The discussion includes perturbations of black holes (Schwarzschild, Reissner-Nordström, Kerr and Kerr-Newman) and relativistic stars (non-rotating and slowly-rotating). The properties of the various families of quasi-normal modes are described, and numerical techniques for calculating quasi-normal modes reviewed. The successes, as well as the limits, of perturbation theory are presented, and its role in the emerging era of numerical relativity and supercomputers is discussed.

[]

https://arxiv.org/pdf/gr-qc/9909058.pdf

2014NatCo...5.4458X

Rediscovering black phosphorus as an anisotropic layered material for optoelectronics and electronics

2014-01-01

['-', '-']

[]

Graphene and transition metal dichalcogenides (TMDCs) are the two major types of layered materials under intensive investigation. However, the zero-bandgap nature of graphene and the relatively low mobility in TMDCs limit their applications. Here we reintroduce black phosphorus (BP), the most stable allotrope of phosphorus with strong intrinsic in-plane anisotropy, to the layered-material family. For 15-nm-thick BP, we measure a Hall mobility of 1,000 and 600 cm<SUP>2 </SUP>V<SUP>-1 </SUP>s<SUP>-1</SUP> for holes along the light (x) and heavy (y) effective mass directions at 120 K. BP thin films also exhibit large and anisotropic in-plane optical conductivity from 2 to 5 μm. Field-effect transistors using 5 nm BP along x direction exhibit an on-off current ratio exceeding 10<SUP>5</SUP>, a field-effect mobility of 205 cm<SUP>2 </SUP>V<SUP>-1 </SUP>s<SUP>-1</SUP>, and good current saturation characteristics all at room temperature. BP shows great potential for thin-film electronics, infrared optoelectronics and novel devices in which anisotropic properties are desirable.

[]

https://arxiv.org/pdf/1402.0270.pdf

2003ApJ...589L..21M

The Relation between Black Hole Mass, Bulge Mass, and Near-Infrared Luminosity

2003-01-01

['black hole physics', 'galaxies bulges', 'galaxies fundamental parameters', 'galaxies nuclei', 'astrophysics']

[]

We present new accurate near-infrared (NIR) spheroid (bulge) structural parameters obtained by a two-dimensional image analysis of all galaxies with a direct black hole (BH) mass determination. As expected, NIR bulge luminosities L<SUB>bul</SUB> and BH masses are tightly correlated, and if we consider only those galaxies with a secure BH mass measurement and an accurate L<SUB>bul</SUB> (27 objects), the spread of M<SUB>BH</SUB>-L<SUB>bul</SUB> is similar to M<SUB>BH</SUB>-σ<SUB>e</SUB>, where σ<SUB>e</SUB> is the effective stellar velocity dispersion. We find an intrinsic rms scatter of ~=0.3 dex in logM<SUB>BH</SUB>. By combining the bulge effective radii R<SUB>e</SUB> measured in our analysis with σ<SUB>e</SUB>, we find a tight linear correlation (rms~=0.25 dex) between M<SUB>BH</SUB> and the virial bulge mass (~R<SUB>e</SUB>σ<SUP>2</SUP><SUB>e</SUB>), with &lt;M<SUB>BH</SUB>/M<SUB>bul</SUB>&gt;~0.002. A partial correlation analysis shows that M<SUB>BH</SUB> depends on both σ<SUB>e</SUB> and R<SUB>e</SUB> and that both variables are necessary to drive the correlations between M<SUB>BH</SUB> and other bulge properties.

[]

https://arxiv.org/pdf/astro-ph/0304274.pdf

1995ApJ...452..710N

Advection-dominated Accretion: Underfed Black Holes and Neutron Stars

1995-01-01

['accretion', 'accretion disks', 'black hole physics', 'radiation', '-', 'astrophysics']

[]

We describe new optically thin solutions for rotating accretion flows around black holes and neutron stars. These solutions are advection dominated, so that most of the viscously dissipated energy is advected radially with the flow. We model the accreting gas as a two-temperature plasma and include cooling by bremsstrahlung, synchrotron, and Comptonization. We obtain electron temperatures T<SUB>e</SUB> 10<SUP>8.5</SUP>-10<SUP>10</SUP> K. <P />The new solutions are present only for mass accretion rates M<SUP>ṡ</SUP><SUB>crit</SUB> less than a critical rate A crit which we calculate as a function of radius R and viscosity parameter α. For M<SUP>ṡ</SUP> &lt; M<SUP>ṡ</SUP><SUB>crit</SUB> we show that there are three equilibrium branches of solutions. One of the branches corresponds to a cool optically thick flow which is the well-known thin disk solution of Shakura &amp; Sunyaev Another branch corresponds to a hot optically thin flow, discovered originally by Shapiro, Lightman, &amp; Eardley (SLE). This solution is thermally unstable. The third branch corresponds to our new advection-dominated solution. This solution is hotter and more optically thin than the SLE solution but is viscously and thermally stable. It is related to the ion torus model of Rees et al. and may potentially explain the hard X-ray and γ-ray emission from X-ray binaries and active galactic nuclei. <P />For M<SUP>ṡ</SUP> &lt; M<SUP>ṡ</SUP><SUB>crit</SUB>, our work suggests that an accretion flow can choose between two distinct states, namely, the thin disk solution and the new advection-dominated solution, both of which are apparently stable. We argue that, in certain circumstances, it is only the latter solution that is truly stable, and that a thin disk will spontaneously evaporate and convert itself into an advection-dominated flow. Even for M<SUP>ṡ</SUP><SUB>crit</SUB> we suggest that a thin disk may evaporate partially so that a fraction of the accretion occurs via an advection-dominated hot corona. If these ideas are correct, then optically thin advection-dominated flows must be very widespread, possibly the most common form of sub-Eddington accretion in black holes. <P />Our calculations indicate that advection-dominated accretion on black holes differs considerably from similar flows around neutron stars. The crucial physical difference, which has been mentioned previously in the literature, is that in the former the advected energy is lost into the hole, whereas in the latter it is thermalized and re-radiated at the stellar surface, thereby providing soft photons which can Compton-cool the accreting gas. We obtain M<SUP>ṡ</SUP><SUB>crit</SUB> ∼ α<SUP>2</SUP>M<SUP>ṡ</SUP><SUB>Edd</SUB> for accreting black holes, independent of the black hole mass, whereas it is ∼0.1α<SUP>2</SUP>M<SUP>ṡ</SUP><SUB>Edd</SUB> for neutron stars. Advection-dominated accretion is therefore more likely to occur in accreting black holes, and these systems will be underluminous for their M<SUP>ṡ</SUP> because the bulk of the energy is advected into the hole rather than being radiated. We find that T<SUB>e</SUB> in accreting black hole flows rises up to ∼10<SUP>9</SUP> 10<SUP>10</SUP> K, compared to T<SUB>e</SUB> ∼ 10<SUP>8.5</SUP>-10<SUP>9</SUP> K in neutron star systems. Spectra of accreting black holes are therefore expected to be harder than those of accreting neutron stars. Pair effects are also more likely in black hole systems, though only at higher A than those we consider.

[]

https://arxiv.org/pdf/astro-ph/9411059.pdf

2020ApJ...896L..44A

GW190814: Gravitational Waves from the Coalescence of a 23 Solar Mass Black Hole with a 2.6 Solar Mass Compact Object

2020-01-01

['-', '-', '-', '-', 'gravitational waves', '-', '-', '-', '-', '-', '-', '-', '-', '-']

[]

We report the observation of a compact binary coalescence involving a 22.2-24.3 M<SUB>⊙</SUB> black hole and a compact object with a mass of 2.50-2.67 M<SUB>⊙</SUB> (all measurements quoted at the 90% credible level). The gravitational-wave signal, GW190814, was observed during LIGO's and Virgo's third observing run on 2019 August 14 at 21:10:39 UTC and has a signal-to-noise ratio of 25 in the three-detector network. The source was localized to 18.5 deg<SUP>2</SUP> at a distance of ${241}_{-45}^{+41}$ Mpc; no electromagnetic counterpart has been confirmed to date. The source has the most unequal mass ratio yet measured with gravitational waves, ${0.112}_{-0.009}^{+0.008}$ , and its secondary component is either the lightest black hole or the heaviest neutron star ever discovered in a double compact-object system. The dimensionless spin of the primary black hole is tightly constrained to ≤0.07. Tests of general relativity reveal no measurable deviations from the theory, and its prediction of higher-multipole emission is confirmed at high confidence. We estimate a merger rate density of 1-23 Gpc<SUP>-3</SUP> yr<SUP>-1</SUP> for the new class of binary coalescence sources that GW190814 represents. Astrophysical models predict that binaries with mass ratios similar to this event can form through several channels, but are unlikely to have formed in globular clusters. However, the combination of mass ratio, component masses, and the inferred merger rate for this event challenges all current models of the formation and mass distribution of compact-object binaries.

[]

https://arxiv.org/pdf/2006.12611.pdf

2004ApJ...604L..89H

On the Black Hole Mass-Bulge Mass Relation

2004-01-01

['galaxies bulges', 'galaxies kinematics and dynamics', 'astrophysics']

[]

We have reexamined the relation between the mass of the central black holes in nearby galaxies, M<SUB>bh</SUB>, and the stellar mass of the surrounding spheroid or bulge, M<SUB>bulge</SUB>. For a total of 30 galaxies bulge masses were derived through Jeans equation modeling or adopted from dynamical models in the literature. In stellar mass-to-light ratios, the spheroids and bulges span a range of a factor of 8. The bulge masses were related to well-determined black hole masses taken from the literature. With these improved values for M<SUB>bh</SUB>, compared to Magorrian et al., and our redetermination of M<SUB>bulge</SUB>, we find that the M<SUB>bh</SUB>-M<SUB>bulge</SUB> relation becomes very tight. We find M<SUB>bh</SUB>~M<SUP>1.12+/-0.06</SUP><SUB>bulge</SUB> with an observed scatter of &lt;~0.30 dex, a fraction of which can be attributed to measurement errors. The scatter in this relation is therefore comparable to the scatter in the relations of M<SUB>bh</SUB> with σ and the stellar concentration. These results confirm and refine the work of Marconi &amp; Hunt. For M<SUB>bulge</SUB>~5×10<SUP>10</SUP> M<SUB>solar</SUB> the median black hole mass is 0.14%+/-0.04% of the bulge mass.

[]

https://arxiv.org/pdf/astro-ph/0402376.pdf

2013JHEP...02..062A

Black holes: complementarity or firewalls?

2013-01-01

['black hole physics', '-', '-', '-']

[]

We argue that the following three statements cannot all be true: (i) Hawking radiation is in a pure state, (ii) the information carried by the radiation is emitted from the region near the horizon, with low energy effective field theory valid beyond some microscopic distance from the horizon, and (iii) the infalling observer encounters nothing unusual at the horizon. Perhaps the most conservative resolution is that the infalling observer burns up at the horizon. Alternatives would seem to require novel dynamics that nevertheless cause notable violations of semiclassical physics at macroscopic distances from the horizon.

[]

https://arxiv.org/pdf/1207.3123.pdf

2004MNRAS.351..169M

Local supermassive black holes, relics of active galactic nuclei and the X-ray background

2004-01-01

['black hole physics', 'galaxies active', 'galaxies evolution', 'galaxies nuclei', 'galaxies quasars', 'cosmology miscellaneous', 'astrophysics']

[]

We quantify the importance of mass accretion during active galactic nuclei (AGN) phases in the growth of supermassive black holes (BHs) by comparing the mass function of black holes in the Local Universe with that expected from AGN relics, which are black holes grown entirely with mass accretion during AGN phases. The local BH mass function (BHMF) is estimated by applying the well-known correlations between BH mass, bulge luminosity and stellar velocity dispersion to galaxy luminosity and velocity functions. We find that different correlations provide the same BHMF only if they have the same intrinsic dispersion. The density of supermassive black holes in the Local Universe that we estimate is ρ<SUB>BH</SUB>= 4.6<SUP>+1.9</SUP><SUB>-1.4</SUB>h<SUP>2</SUP><SUB>0.7</SUB>× 10<SUP>5</SUP> M<SUB>solar</SUB> Mpc<SUP>-3</SUP>. The relic BHMF is derived from the continuity equation with the only assumption that AGN activity is due to accretion on to massive BHs and that merging is not important. We find that the relic BHMF at z= 0 is generated mainly at z &lt; 3 where the major part of the growth of a BH takes place. Moreover, BH growth is antihierarchical in the sense that smaller BHs (M<SUB>BH</SUB> &lt; 10<SUP>7</SUP> M<SUB>solar</SUB>) grow at lower redshifts (z &lt; 1) with respect to more massive ones (z~ 1-3). Unlike previous work, we find that the BHMF of AGN relics is perfectly consistent with the local BHMF, indicating that local BHs were mainly grown during AGN activity. This agreement is obtained while satisfying, at the same time, the constraints imposed from the X-ray background (XRB). The comparison between the local and relic BHMFs also suggests that the merging process is not important in shaping the relic BHMF, at least at low redshifts (z &lt; 3), and allows us to estimate the average radiative efficiency (ɛ), the ratio between emitted and Eddington luminosity (λ) and the average lifetime of active BHs. Our analysis thus suggests the following scenario: local BHs grew during AGN phases in which accreting matter was converted into radiation with efficiencies ɛ= 0.04-0.16 and emitted at a fraction λ= 0.1-1.7 of the Eddington luminosity. The average total lifetime of these active phases ranges from ~= 4.5 × 10<SUP>8</SUP> yr for M<SUB>BH</SUB> &lt; 10<SUP>8</SUP> M<SUB>solar</SUB> to ~= 1.5 × 10<SUP>8</SUP> yr for M<SUB>BH</SUB> &gt; 10<SUP>9</SUP> M<SUB>solar</SUB>, but can become as large as ~10<SUP>9</SUP> yr for the lowest acceptable ɛ and λ values.

[]

https://arxiv.org/pdf/astro-ph/0311619.pdf

2009ApJ...692.1075G

Monitoring Stellar Orbits Around the Massive Black Hole in the Galactic Center

2009-01-01

['black hole physics', 'astrometry', 'galaxy center', 'astronomy infrared', 'astrophysics']

[]

We present the results of 16 years of monitoring stellar orbits around the massive black hole in the center of the Milky Way, using high-resolution near-infrared techniques. This work refines our previous analysis mainly by greatly improving the definition of the coordinate system, which reaches a long-term astrometric accuracy of ≈300 μas, and by investigating in detail the individual systematic error contributions. The combination of a long-time baseline and the excellent astrometric accuracy of adaptive optics data allows us to determine orbits of 28 stars, including the star S2, which has completed a full revolution since our monitoring began. Our main results are: all stellar orbits are fit extremely well by a single-point-mass potential to within the astrometric uncertainties, which are now ≈6× better than in previous studies. The central object mass is (4.31 ± 0.06|_{stat} ± 0.36|_{R_0})× 10^6 M_⊙, where the fractional statistical error of 1.5% is nearly independent from R <SUB>0</SUB>, and the main uncertainty is due to the uncertainty in R <SUB>0</SUB>. Our current best estimate for the distance to the Galactic center is R <SUB>0</SUB> = 8.33 ± 0.35 kpc. The dominant errors in this value are systematic. The mass scales with distance as (3.95 ± 0.06) × 10<SUP>6</SUP>(R <SUB>0</SUB>/8 kpc)<SUP>2.19</SUP> M <SUB>sun</SUB>. The orientations of orbital angular momenta for stars in the central arcsecond are random. We identify six of the stars with orbital solutions as late-type stars, and six early-type stars as members of the clockwise-rotating disk system, as was previously proposed. We constrain the extended dark mass enclosed between the pericenter and apocenter of S2 at less than 0.066, at the 99% confidence level, of the mass of Sgr A*. This is two orders of magnitudes larger than what one would expect from other theoretical and observational estimates.

[]

https://arxiv.org/pdf/0810.4674.pdf

2008ApJ...689.1044G

Measuring Distance and Properties of the Milky Way's Central Supermassive Black Hole with Stellar Orbits

2008-01-01

['black hole physics', 'galaxy center', 'galaxy kinematics and dynamics', 'astronomy infrared', 'techniques high angular resolution', 'astrophysics']

[]

We report new precision measurements of the properties of our Galaxy's supermassive black hole. Based on astrometric (1995-2007) and radial velocity (RV; 2000-2007) measurements from the W. M. Keck 10 m telescopes, a fully unconstrained Keplerian orbit for the short-period star S0-2 provides values for the distance (R<SUB>0</SUB>) of 8.0 +/- 0.6 kpc, the enclosed mass (M<SUB>bh</SUB>) of 4.1 +/- 0.6 × 10<SUP>6</SUP> M<SUB>⊙</SUB>, and the black hole's RV, which is consistent with zero with 30 km s<SUP>-1</SUP> uncertainty. If the black hole is assumed to be at rest with respect to the Galaxy (e.g., has no massive companion to induce motion), we can further constrain the fit, obtaining R<SUB>0</SUB> = 8.4 +/- 0.4 kpc and M<SUB>bh</SUB> = 4.5 +/- 0.4 × 10<SUP>6</SUP> M<SUB>⊙</SUB>. More complex models constrain the extended dark mass distribution to be less than 3-4 × 10<SUP>5</SUP> M<SUB>⊙</SUB> within 0.01 pc, ~100 times higher than predictions from stellar and stellar remnant models. For all models, we identify transient astrometric shifts from source confusion (up to 5 times the astrometric error) and the assumptions regarding the black hole's radial motion as previously unrecognized limitations on orbital accuracy and the usefulness of fainter stars. Future astrometric and RV observations will remedy these effects. Our estimates of R<SUB>0</SUB> and the Galaxy's local rotation speed, which it is derived from combining R<SUB>0</SUB> with the apparent proper motion of Sgr A*, (θ<SUB>0</SUB> = 229 +/- 18 km s<SUP>-1</SUP>), are compatible with measurements made using other methods. The increased black hole mass found in this study, compared to that determined using projected mass estimators, implies a longer period for the innermost stable orbit, longer resonant relaxation timescales for stars in the vicinity of the black hole and a better agreement with the M<SUB>bh</SUB>-σ relation.

[]

https://arxiv.org/pdf/0808.2870.pdf

2008ApJS..175..356H

A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies. I. Galaxy Mergers and Quasar Activity

2008-01-01

['cosmology theory', 'galaxies active', 'galaxies evolution', 'galaxies quasars', 'astrophysics']

[]

We develop a model for the cosmological role of mergers in the evolution of starbursts, quasars, and spheroidal galaxies. By combining theoretically well-constrained halo and subhalo mass functions as a function of redshift and environment with empirical halo occupation models, we can estimate where galaxies of given properties live at a particular epoch. This allows us to calculate, in an a priori cosmological manner, where major galaxy-galaxy mergers occur and what kinds of galaxies merge, at all redshifts. We compare this with the observed mass functions, clustering, fractions as a function of halo and galaxy mass, and small-scale environments of mergers, and we show that this approach yields robust estimates in good agreement with observations and can be extended to predict detailed properties of mergers. Making the simple Ansatz that major, gas-rich mergers cause quasar activity (but not strictly assuming they are the only triggering mechanism), we demonstrate that this model naturally reproduces the observed rise and fall of the quasar luminosity density at z = 0-6, as well as quasar luminosity functions, fractions, host galaxy colors, and clustering as a function of redshift and luminosity. The recent observed excess of quasar clustering on small scales at z ~ 0.2-2.5 is a natural prediction of our model, as mergers will preferentially occur in regions with excess small-scale galaxy overdensities. In fact, we demonstrate that quasar environments at all observed redshifts correspond closely to the empirically determined small group scale, where major mergers of ~L<SUB>*</SUB> gas-rich galaxies will be most efficient. We contrast this with a secular model in which quasar activity is driven by bars or other disk instabilities, and we show that, while these modes of fueling probably dominate the high Eddington ratio population at Seyfert luminosities (significant at z = 0), the constraints from quasar clustering, observed pseudobulge populations, and disk mass functions suggest that they are a small contributor to the z gtrsim 1 quasar luminosity density, which is dominated by massive BHs in predominantly classical spheroids formed in mergers. Similarly, low-luminosity Seyferts do not show a clustering excess on small scales, in agreement with the natural prediction of secular models, but bright quasars at all redshifts do so. We also compare recent observations of the colors of quasar host galaxies and show that these correspond to the colors of recent merger remnants, in the transition region between the blue cloud and the red sequence, and are distinct from the colors of systems with observed bars or strong disk instabilities. Even the most extreme secular models, in which all bulge (and therefore BH) formation proceeds via disk instability, are forced to assume that this instability acts before the (dynamically inevitable) mergers, and therefore predict a history for the quasar luminosity density that is shifted to earlier times, in disagreement with observations. Our model provides a powerful means to predict the abundance and nature of mergers and to contrast cosmologically motivated predictions of merger products such as starbursts and active galactic nuclei.

[]

https://arxiv.org/pdf/0706.1243.pdf

2003JHEP...04..021M

Eternal black holes in anti-de Sitter

2003-01-01

['-', '-']

[]

We propose a dual non-perturbative description for maximally extended Schwarzschild Anti-de-Sitter spacetimes. The description involves two copies of the conformal field theory associated to the AdS spacetime and an initial entangled state. In this context we also discuss a version of the information loss paradox and its resolution.

[]

https://arxiv.org/pdf/hep-th/0106112.pdf

1999PhRvD..60f4018C

Charged AdS black holes and catastrophic holography

1999-01-01

['-', '-', '-', '-', '-']

[]

We compute the properties of a class of charged black holes in anti-de Sitter space-time, in diverse dimensions. These black holes are solutions of consistent Einstein-Maxwell truncations of gauged supergravities, which are shown to arise from the inclusion of rotation in the transverse space. We uncover rich thermodynamic phase structures for these systems, which display classic critical phenomena, including structures isomorphic to the van der Waals-Maxwell liquid-gas system. In that case, the phases are controlled by the universal ``cusp'' and ``swallowtail'' shapes familiar from catastrophe theory. All of the thermodynamics is consistent with field theory interpretations via holography, where the dual field theories can sometimes be found on the world volumes of coincident rotating branes.

[]

https://arxiv.org/pdf/hep-th/9902170.pdf

1999MNRAS.303L...1B

On the fate of gas accreting at a low rate on to a black hole

1999-01-01

['accretion', 'accretion disks', 'black hole physics', 'hydrodynamics', 'astrophysics']

[]

Gas supplied conservatively to a black hole at rates well below the Eddington rate may not be able to radiate effectively and the net energy flux, including the energy transported by the viscous torque, is likely to be close to zero at all radii. This has the consequence that the gas accretes with positive energy so that it may escape. Accordingly, we propose that only a small fraction of the gas supplied actually falls on to the black hole, and that the binding energy it releases is transported radially outward by the torque so as to drive away the remainder in the form of a wind. This is a generalization of and an alternative to an `ADAF' solution. Some observational implications and possible ways to distinguish these two types of flow are briefly discussed.

[]

https://arxiv.org/pdf/astro-ph/9809083.pdf

1999PhRvL..82.4971C

Effective Field Theory, Black Holes, and the Cosmological Constant

1999-01-01

['-', '-', '-']

[]

Bekenstein has proposed the bound S&lt;=πM<SUP>2</SUP><SUB>P</SUB>L<SUP>2</SUP> on the total entropy S in a volume L<SUP>3</SUP>. This nonextensive scaling suggests that quantum field theory breaks down in large volume. To reconcile this breakdown with the success of local quantum field theory in describing observed particle phenomenology, we propose a relationship between UV and IR cutoffs such that an effective field theory should be a good description of nature. We discuss implications for the cosmological constant problem. We find a limitation on the accuracy which can be achieved by conventional effective field theory.

[]

https://arxiv.org/pdf/hep-th/9803132.pdf

2014JHEP...03..067S

Black holes and the butterfly effect

2014-01-01

['-', 'black hole physics', '-']

[]

We use holography to study sensitive dependence on initial conditions in strongly coupled field theories. Specifically, we mildly perturb a thermofield double state by adding a small number of quanta on one side. If these quanta are released a scrambling time in the past, they destroy the local two-sided correlations present in the unperturbed state. The corresponding bulk geometry is a two-sided AdS black hole, and the key effect is the blueshift of the early infalling quanta relative to the t = 0 slice, creating a shock wave. We comment on string- and Planck-scale corrections to this setup, and discuss points that may be relevant to the firewall controversy.

[]

https://arxiv.org/pdf/1306.0622.pdf

2019ApJ...875L...6E

First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole

2019-01-01

['black hole physics', 'galaxies', 'gravitation', 'techniques high angular resolution', 'techniques interferometric', '-', '-', '-']

[]

We present measurements of the properties of the central radio source in M87 using Event Horizon Telescope data obtained during the 2017 campaign. We develop and fit geometric crescent models (asymmetric rings with interior brightness depressions) using two independent sampling algorithms that consider distinct representations of the visibility data. We show that the crescent family of models is statistically preferred over other comparably complex geometric models that we explore. We calibrate the geometric model parameters using general relativistic magnetohydrodynamic (GRMHD) models of the emission region and estimate physical properties of the source. We further fit images generated from GRMHD models directly to the data. We compare the derived emission region and black hole parameters from these analyses with those recovered from reconstructed images. There is a remarkable consistency among all methods and data sets. We find that &gt;50% of the total flux at arcsecond scales comes from near the horizon, and that the emission is dramatically suppressed interior to this region by a factor &gt;10, providing direct evidence of the predicted shadow of a black hole. Across all methods, we measure a crescent diameter of 42 ± 3 μas and constrain its fractional width to be &lt;0.5. Associating the crescent feature with the emission surrounding the black hole shadow, we infer an angular gravitational radius of GM/Dc <SUP>2</SUP> = 3.8 ± 0.4 μas. Folding in a distance measurement of 16.8<SUB>-0.7</SUB><SUP>+0.8</SUP> Mpc gives a black hole mass of M=6.5+/- 0.2| <SUB>stat</SUB>+/- 0.7| <SUB>sys</SUB>× 10<SUP>9</SUP> M<SUB>⊙</SUB>. This measurement from lensed emission near the event horizon is consistent with the presence of a central Kerr black hole, as predicted by the general theory of relativity.

[]

https://arxiv.org/pdf/1906.11243.pdf

2016PhRvX...6d1015A

Binary Black Hole Mergers in the First Advanced LIGO Observing Run

2016-01-01

['-', '-']

[]

The first observational run of the Advanced LIGO detectors, from September 12, 2015 to January 19, 2016, saw the first detections of gravitational waves from binary black hole mergers. In this paper, we present full results from a search for binary black hole merger signals with total masses up to 100 M<SUB>⊙</SUB> and detailed implications from our observations of these systems. Our search, based on general-relativistic models of gravitational-wave signals from binary black hole systems, unambiguously identified two signals, GW150914 and GW151226, with a significance of greater than 5 σ over the observing period. It also identified a third possible signal, LVT151012, with substantially lower significance and with an 87% probability of being of astrophysical origin. We provide detailed estimates of the parameters of the observed systems. Both GW150914 and GW151226 provide an unprecedented opportunity to study the two-body motion of a compact-object binary in the large velocity, highly nonlinear regime. We do not observe any deviations from general relativity, and we place improved empirical bounds on several high-order post-Newtonian coefficients. From our observations, we infer stellar-mass binary black hole merger rates lying in the range 9 - 240 Gpc<SUP>-3</SUP> yr<SUP>-1</SUP> . These observations are beginning to inform astrophysical predictions of binary black hole formation rates and indicate that future observing runs of the Advanced detector network will yield many more gravitational-wave detections.

[]

https://arxiv.org/pdf/1606.04856.pdf

2014ARA&A..52..529Y

Hot Accretion Flows Around Black Holes

2014-01-01

['-']

[]

Black hole accretion flows can be divided into two broad classes: cold and hot. Whereas cold accretion flows consist of cool optically thick gas and are found at relatively high mass accretion rates, hot accretion flows, the topic of this review, are virially hot and optically thin, and occur at lower mass accretion rates. They are described by accretion solutions such as the advection-dominated accretion flow and luminous hot accretion flow. Because of energy advection, the radiative efficiency of these flows is in general lower than that of a standard thin accretion disk. Moreover, the efficiency decreases with decreasing mass accretion rate. Observations show that hot accretion flows are associated with jets. In addition, theoretical arguments suggest that hot flows should produce strong winds. Hot accretion flows are believed to be present in low-luminosity active galactic nuclei and in black hole X-ray binaries in the hard and quiescent states. The prototype is Sgr A*, the ultralow-luminosity supermassive black hole at our Galactic center. The jet, wind, and radiation from a supermassive black hole with a hot accretion flow can interact with the external interstellar medium and modify the evolution of the host galaxy.

[]

https://arxiv.org/pdf/1401.0586.pdf

2004MNRAS.355.1105F

Towards a unified model for black hole X-ray binary jets

2004-01-01

['accretion', 'accretion disks', 'black hole physics', 'ism jets and outflows', 'astronomy x rays', 'astrophysics']

[]

We present a unified semiquantitative model for the disc-jet coupling in black hole X-ray binary systems. In the process we have compiled observational aspects from the existing literature, as well as performing new analyses. We argue that during the rising phase of a black hole transient outburst the steady jet known to be associated with the canonical `low/hard' state persists while the X-ray spectrum initially softens. Subsequently, the jet becomes unstable and an optically thin radio outburst is always associated with the soft X-ray peak at the end of this phase of softening. This peak corresponds to a `soft very high state' or `steep power-law' state. Softer X-ray states are not associated with `core' radio emission. We further demonstrate quantitatively that the transient jets associated with these optically thin events are considerably more relativistic than those in the `low/hard' X-ray state. This in turn implies that, as the disc makes its collapse inwards, the jet Lorentz factor rapidly increases, resulting in an internal shock in the outflow, which is the cause of the observed optically thin radio emission. We provide simple estimates for the efficiency of such a shock in the collision of a fast jet with a previously generated outflow that is only mildly relativistic. In addition, we estimate the jet power for a number of such transient events as a function of X-ray luminosity, and find them to be comparable to an extrapolation of the functions estimated for the `low/hard' state jets. The normalization may be larger, however, which may suggest a contribution from some other power source such as black hole spin, for the transient jets. Finally, we attempt to fit these results together into a coherent semiquantitative model for the disc-jet coupling in all black hole X-ray binary systems.

[]

https://arxiv.org/pdf/astro-ph/0409360.pdf

2009CQGra..26s5011K

Enthalpy and the mechanics of AdS black holes

2009-01-01

['-']

[]

We present geometric derivations of the Smarr formula for static AdS black holes and an expanded first law that includes variations in the cosmological constant. These two results are further related by a scaling argument based on Euler's theorem. The key new ingredient in the constructions is a two-form potential for the static Killing field. Surface integrals of the Killing potential determine the coefficient of the variation of Λ in the first law. This coefficient is proportional to a finite, effective volume for the region outside the AdS black hole horizon, which can also be interpreted as minus the volume excluded from a spatial slice by the black hole horizon. This effective volume also contributes to the Smarr formula. Since Λ is naturally thought of as a pressure, the new term in the first law has the form of effective volume times change in pressure that arises in the variation of the enthalpy in classical thermodynamics. This and related arguments suggest that the mass of an AdS black hole should be interpreted as the enthalpy of the spacetime.

[]

https://arxiv.org/pdf/0904.2765.pdf

2007JHEP...06..060A

The string landscape, black holes and gravity as the weakest force

2007-01-01

['-', '-']

[]

We conjecture a general upper bound on the strength of gravity relative to gauge forces in quantum gravity. This implies, in particular, that in a four-dimensional theory with gravity and a U(1) gauge field with gauge coupling g, there is a new ultraviolet scale Λ = gM<SUB>Pl</SUB>, invisible to the low-energy effective field theorist, which sets a cutoff on the validity of the effective theory. Moreover, there is some light charged particle with mass smaller than or equal to Λ. The bound is motivated by arguments involving holography and absence of remnants, the (in) stability of black holes as well as the non-existence of global symmetries in string theory. A sharp form of the conjecture is that there are always light ``elementary'' electric and magnetic objects with a mass/charge ratio smaller than the corresponding ratio for macroscopic extremal black holes, allowing extremal black holes to decay. This conjecture is supported by a number of non-trivial examples in string theory. It implies the necessary presence of new physics beneath the Planck scale, not far from the GUT scale, and explains why some apparently natural models of inflation resist an embedding in string theory.

[]

https://arxiv.org/pdf/hep-th/0601001.pdf

2013ForPh..61..781M

Cool horizons for entangled black holes

2013-01-01

['-']

[]

General relativity contains solutions in which two distant black holes are connected through the interior via a wormhole, or Einstein-Rosen bridge. These solutions can be interpreted as maximally entangled states of two black holes that form a complex EPR pair. We suggest that similar bridges might be present for more general entangled states. In the case of entangled black holes one can formulate versions of the AMPS(S) paradoxes and resolve them. This suggests possible resolutions of the firewall paradoxes for more general situations.

[]

https://arxiv.org/pdf/1306.0533.pdf

1997ApJ...489..865E

Advection-Dominated Accretion and the Spectral States of Black Hole X-Ray Binaries: Application to Nova Muscae 1991

1997-01-01

['accretion', 'accretion disks', 'black hole physics', 'astronomy x rays', 'astrophysics']

[]

Black hole X-ray binaries (BHXBs) are known to display five distinct spectral states. In order of increasing luminosity these are the quiescent state, low state, intermediate state, high state, and very high state. We present a self-consistent model of accretion flows around black holes that unifies all of these states except the very high state. The model is an extension of the following paradigm, which has been applied successfully to the quiescent state. The accretion flow consists of two zones, an inner advection-dominated accretion flow (ADAF) that extends from the black hole horizon to a transition radius r<SUB>tr</SUB>, and an outer thin accretion disk that is present beyond r<SUB>tr</SUB>. Above the disk is a hot corona, which is a continuation of the inner ADAF. The model consistently treats the dynamics of the accreting gas, the thermal balance of the ions and electrons in the two-temperature ADAF and corona, and the radiation processes that produce the observed spectrum. <P />At low mass accretion rates, ṁ&lt;~0.01 (in Eddington units), the inner ADAF zone in the model radiates extremely inefficiently, and the outer thin disk is restricted to large radii (r<SUB>tr</SUB> ~ 10<SUP>2</SUP>-10<SUP>4</SUP>, in Schwarzschild units). The luminosity therefore is low, and this configuration is identified with the quiescent state. For ṁ&gt;~0.01 and up to a critical value ṁ<SUB>crit</SUB>~0.08, the radiative efficiency of the ADAF increases rapidly and the system becomes fairly luminous. The spectrum is very hard and peaks around 100 keV. This is the low state. The exact value of ṁ<SUB>crit</SUB> depends on the viscosity parameter α (ṁ<SUB>crit</SUB>~1.3α<SUP>2</SUP> the paper assumes α = 0.25). For values of ṁ&gt;ṁ<SUB>crit</SUB> and up to a second critical value about 10% higher, the ADAF progressively shrinks in size, the transition radius decreases, and the X-ray spectrum changes continuously from hard to soft. We identify this stage with the intermediate state. Finally, when ṁ is sufficiently large, the inner ADAF zone disappears altogether and the thin accretion disk extends down to the marginally stable orbit. The spectrum is dominated by an ultrasoft component with a weak hard tail. This is the high state. Model spectra calculated with this unified scenario agree well with observations of the quiescent, low, intermediate, and high states. Moreover, the model provides a natural explanation for the low state to high state transition in BHXBs. We also make a tentative proposal for the very high state, but this aspect of the model is less secure. <P />An important feature of the model is that it is essentially parameter free. We test the model against observations of the soft X-ray transient Nova Muscae during its 1991 outburst. The model reproduces the observed light curves and spectra surprisingly well and makes a number of predictions that can be tested by observations of other BHXBs.

[]

https://arxiv.org/pdf/astro-ph/9705237.pdf

2006PhRvL..96k1101C

Accurate Evolutions of Orbiting Black-Hole Binaries without Excision

2006-01-01

['-', '-', '-', '-', 'methods numerical', '-', 'perturbation theory', '-', 'waves', '-', '-', 'astrophysics']

[]

We present a new algorithm for evolving orbiting black-hole binaries that does not require excision or a corotating shift. Our algorithm is based on a novel technique to handle the singular puncture conformal factor. This system, based on the Baumgarte-Shapiro-Shibata-Nakamura formulation of Einstein’s equations, when used with a “precollapsed” initial lapse, is nonsingular at the start of the evolution and remains nonsingular and stable provided that a good choice is made for the gauge. As a test case, we use this technique to fully evolve orbiting black-hole binaries from near the innermost stable circular orbit regime. We show fourth-order convergence of waveforms and compute the radiated gravitational energy and angular momentum from the plunge. These results are in good agreement with those predicted by the Lazarus approach.

[]

https://arxiv.org/pdf/gr-qc/0511048.pdf

2019ApJ...875L...4E

First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole

2019-01-01

['black hole physics', 'galaxies', 'galaxies jets', 'techniques high angular resolution', 'techniques image processing', 'techniques interferometric', '-', '-', '-']

[]

We present the first Event Horizon Telescope (EHT) images of M87, using observations from April 2017 at 1.3 mm wavelength. These images show a prominent ring with a diameter of ∼40 μas, consistent with the size and shape of the lensed photon orbit encircling the “shadow” of a supermassive black hole. The ring is persistent across four observing nights and shows enhanced brightness in the south. To assess the reliability of these results, we implemented a two-stage imaging procedure. In the first stage, four teams, each blind to the others’ work, produced images of M87 using both an established method (CLEAN) and a newer technique (regularized maximum likelihood). This stage allowed us to avoid shared human bias and to assess common features among independent reconstructions. In the second stage, we reconstructed synthetic data from a large survey of imaging parameters and then compared the results with the corresponding ground truth images. This stage allowed us to select parameters objectively to use when reconstructing images of M87. Across all tests in both stages, the ring diameter and asymmetry remained stable, insensitive to the choice of imaging technique. We describe the EHT imaging procedures, the primary image features in M87, and the dependence of these features on imaging assumptions.

[]

https://arxiv.org/pdf/1906.11241.pdf

2005PhRvL..95l1101P

Evolution of Binary Black-Hole Spacetimes

2005-01-01

['-', '-', '-', 'methods numerical', 'waves', '-', '-', 'astrophysics', '-']

[]

We describe early success in the evolution of binary black-hole spacetimes with a numerical code based on a generalization of harmonic coordinates. Indications are that with sufficient resolution this scheme is capable of evolving binary systems for enough time to extract information about the orbit, merger, and gravitational waves emitted during the event. As an example we show results from the evolution of a binary composed of two equal mass, nonspinning black holes, through a single plunge orbit, merger, and ringdown. The resultant black hole is estimated to be a Kerr black hole with angular momentum parameter a≈0.70. At present, lack of resolution far from the binary prevents an accurate estimate of the energy emitted, though a rough calculation suggests on the order of 5% of the initial rest mass of the system is radiated as gravitational waves during the final orbit and ringdown.

[]

https://arxiv.org/pdf/gr-qc/0507014.pdf

2017ApJ...851L..35A

GW170608: Observation of a 19 Solar-mass Binary Black Hole Coalescence

2017-01-01

['stars binaries general', 'gravitational waves', 'stars black holes', '-', '-']

[]

On 2017 June 8 at 02:01:16.49 UTC, a gravitational-wave (GW) signal from the merger of two stellar-mass black holes was observed by the two Advanced Laser Interferometer Gravitational-Wave Observatory detectors with a network signal-to-noise ratio of 13. This system is the lightest black hole binary so far observed, with component masses of {12}<SUB>-2</SUB><SUP>+7</SUP> {M}<SUB>⊙ </SUB> and {7}<SUB>-2</SUB><SUP>+2</SUP> {M}<SUB>⊙ </SUB> (90% credible intervals). These lie in the range of measured black hole masses in low-mass X-ray binaries, thus allowing us to compare black holes detected through GWs with electromagnetic observations. The source’s luminosity distance is {340}<SUB>-140</SUB><SUP>+140</SUP> {Mpc}, corresponding to redshift {0.07}<SUB>-0.03</SUB><SUP>+0.03</SUP>. We verify that the signal waveform is consistent with the predictions of general relativity.

[]

https://arxiv.org/pdf/1711.05578.pdf

2006ApJ...641..689V

Determining Central Black Hole Masses in Distant Active Galaxies and Quasars. II. Improved Optical and UV Scaling Relationships

2006-01-01

['galaxies active', 'galaxies fundamental parameters', 'galaxies photometry', 'galaxies seyfert', 'galaxies quasars', 'astronomy uv', 'astrophysics']

[]

We present four improved empirical relationships useful for estimating the central black hole mass in nearby AGNs and distant luminous quasars alike using either optical or UV single-epoch spectroscopy. These mass scaling relationships between line widths and luminosity are based on recently improved empirical relationships between the broad-line region size and luminosities in various energy bands and are calibrated to the improved mass measurements of nearby AGNs based on emission-line reverberation mapping. The mass scaling relationship based on the Hβ line luminosity allows mass estimates for low-redshift sources with strong contamination of the optical continuum luminosity by stellar or nonthermal emission, while that based on the C IV λ1549 line dispersion allows mass estimates in cases where only the line dispersion (as opposed to the FWHM) can be reliably determined. We estimate that the absolute uncertainties in masses given by these mass scaling relationships are typically around a factor of 4. We include in an appendix mass estimates for all of the Bright Quasar Survey (PG) quasars for which direct reverberation-based mass measurements are not available. <P />Based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

[]

https://arxiv.org/pdf/astro-ph/0601303.pdf

2011RvMP...83..793K

Quasinormal modes of black holes: From astrophysics to string theory

2011-01-01

['-', '-', 'waves', '-', '-', '-', '-']

[]

Perturbations of black holes, initially considered in the context of possible observations of astrophysical effects, have been studied for the past 10 years in string theory, brane-world models, and quantum gravity. Through the famous gauge/gravity duality, proper oscillations of perturbed black holes, called quasinormal modes, allow for the description of the hydrodynamic regime in the dual finite temperature field theory at strong coupling, which can be used to predict the behavior of quark-gluon plasmas in the nonperturbative regime. On the other hand, the brane-world scenarios assume the existence of extra dimensions in nature, so that multidimensional black holes can be formed in a laboratory experiment. All this stimulated active research in the field of perturbations of higher-dimensional black holes and branes during recent years. In this review recent achievements on various aspects of black hole perturbations are discussed such as decoupling of variables in the perturbation equations, quasinormal modes (with special emphasis on various numerical and analytical methods of calculations), late-time tails, gravitational stability, anti-de Sitter/conformal field theory interpretation of quasinormal modes, and holographic superconductors. We also touch on state-of-the-art observational possibilities for detecting quasinormal modes of black holes.

[]

https://arxiv.org/pdf/1102.4014.pdf

1992PhRvD..45.1005C

Evanescent black holes

1992-01-01

['-', '-', '-', 'black hole physics', '-']

[]

A renormalizable theory of quantum gravity coupled to a dilaton and conformal matter in two space-time dimensions is analyzed. The theory is shown to be exactly solvable classically. Included among the exact classical solutions are configurations describing the formation of a black hole by collapsing matter. The problem of Hawking radiation and back reaction of the metric is analyzed to leading order in a 1/N expansion, where N is the number of matter fields. The results suggest that the collapsing matter radiates away all of its energy before an event horizon has a chance to form, and black holes thereby disappear from the quantum-mechanical spectrum. It is argued that the matter asymptotically approaches a zero-energy ``bound state'' which can carry global quantum numbers and that a unitary S matrix including such states should exist.

[]

https://arxiv.org/pdf/hep-th/9111056.pdf

2013ApJ...764..184M

Revisiting the Scaling Relations of Black Hole Masses and Host Galaxy Properties

2013-01-01

['galaxies nuclei', 'galaxies statistics', '-']

[]

New kinematic data and modeling efforts in the past few years have substantially expanded and revised dynamical measurements of black hole masses (M <SUB>•</SUB>) at the centers of nearby galaxies. Here we compile an updated sample of 72 black holes and their host galaxies, and present revised scaling relations between M <SUB>•</SUB> and stellar velocity dispersion (σ), V-band luminosity (L), and bulge stellar mass (M <SUB>bulge</SUB>), for different galaxy subsamples. Our best-fitting power-law relations for the full galaxy sample are log<SUB>10</SUB>(M <SUB>•</SUB>) = 8.32 + 5.64log<SUB>10</SUB>(σ/200 km s<SUP>-1</SUP>), log<SUB>10</SUB>(M <SUB>•</SUB>) = 9.23 + 1.11log<SUB>10</SUB>(L/10<SUP>11</SUP> L <SUB>⊙</SUB>), and log<SUB>10</SUB>(M <SUB>•</SUB>) = 8.46 + 1.05log<SUB>10</SUB>(M <SUB>bulge</SUB>/10<SUP>11</SUP> M <SUB>⊙</SUB>). A log-quadratic fit to the M <SUB>•</SUB>-σ relation with an additional term of β<SUB>2</SUB> [log<SUB>10</SUB>(σ/200 km s<SUP>-1</SUP>)]<SUP>2</SUP> gives β<SUB>2</SUB> = 1.68 ± 1.82 and does not decrease the intrinsic scatter in M <SUB>•</SUB>. Including 92 additional upper limits on M <SUB>•</SUB> does not change the slope of the M <SUB>•</SUB>-σ relation. When the early- and late-type galaxies are fit separately, we obtain similar slopes of 5.20 and 5.06 for the M <SUB>•</SUB>-σ relation but significantly different intercepts—M <SUB>•</SUB> in early-type galaxies are about two times higher than in late types at a given sigma. Within early-type galaxies, our fits to M <SUB>•</SUB>(σ) give M <SUB>•</SUB> that is about two times higher in galaxies with central core profiles than those with central power-law profiles. Our M <SUB>•</SUB>-L and M <SUB>•</SUB>-M <SUB>bulge</SUB> relations for early-type galaxies are similar to those from earlier compilations, and core and power-law galaxies yield similar L- and M <SUB>bulge</SUB>-based predictions for M <SUB>•</SUB>. When the conventional quadrature method is used to determine the intrinsic scatter in M <SUB>•</SUB>, our data set shows weak evidence for increased scatter at M <SUB>bulge</SUB> &lt; 10<SUP>11</SUP> M <SUB>⊙</SUB> or L<SUB>V</SUB> &lt; 10<SUP>10.3</SUP> L <SUB>⊙</SUB>, while the scatter stays constant for 10<SUP>11</SUP> &lt; M <SUB>bulge</SUB> &lt; 10<SUP>12.3</SUP> M <SUB>⊙</SUB> and 10<SUP>10.3</SUP> &lt; L<SUB>V</SUB> &lt; 10<SUP>11.5</SUP> L <SUB>⊙</SUB>. A Bayesian analysis indicates that a larger sample of M <SUB>•</SUB> measurements would be needed to detect any statistically significant trend in the scatter with galaxy properties.

[]

https://arxiv.org/pdf/1211.2816.pdf

2020PhRvL.125j1102A

GW190521: A Binary Black Hole Merger with a Total Mass of <inline-formula><mml:math display="inline"><mml:mrow><mml:mn>150</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:msub><mml:mrow><mml:mi>M</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">⊙</mml:mo></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula>

2020-01-01

['-', '-', '-']

[]

On May 21, 2019 at 03:02:29 UTC Advanced LIGO and Advanced Virgo observed a short duration gravitational-wave signal, GW190521, with a three-detector network signal-to-noise ratio of 14.7, and an estimated false-alarm rate of 1 in 4900 yr using a search sensitive to generic transients. If GW190521 is from a quasicircular binary inspiral, then the detected signal is consistent with the merger of two black holes with masses of <inline-formula><mml:math display="inline"><mml:mrow><mml:mrow><mml:mn>8</mml:mn><mml:msubsup><mml:mrow><mml:mn>5</mml:mn></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>14</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>21</mml:mn></mml:mrow></mml:msubsup></mml:mrow><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:msub><mml:mrow><mml:mi>M</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">⊙</mml:mo></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula> and <inline-formula><mml:math display="inline"><mml:mrow><mml:mrow><mml:mn>6</mml:mn><mml:msubsup><mml:mrow><mml:mn>6</mml:mn></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>18</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>17</mml:mn></mml:mrow></mml:msubsup></mml:mrow><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:msub><mml:mrow><mml:mi>M</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">⊙</mml:mo></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula> (90% credible intervals). We infer that the primary black hole mass lies within the gap produced by (pulsational) pair-instability supernova processes, with only a 0.32% probability of being below <inline-formula><mml:math display="inline"><mml:mn>65</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:msub><mml:mi>M</mml:mi><mml:mo stretchy="false">⊙</mml:mo></mml:msub></mml:math></inline-formula>. We calculate the mass of the remnant to be <inline-formula><mml:math display="inline"><mml:mrow><mml:mrow><mml:mn>14</mml:mn><mml:msubsup><mml:mrow><mml:mn>2</mml:mn></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>16</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>28</mml:mn></mml:mrow></mml:msubsup></mml:mrow><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:msub><mml:mrow><mml:mi>M</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">⊙</mml:mo></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula>, which can be considered an intermediate mass black hole (IMBH). The luminosity distance of the source is <inline-formula><mml:math display="inline"><mml:mrow><mml:msubsup><mml:mrow><mml:mn>5.3</mml:mn></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>2.6</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>2.4</mml:mn></mml:mrow></mml:msubsup><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>Gpc</mml:mi></mml:mrow></mml:math></inline-formula>, corresponding to a redshift of <inline-formula><mml:math display="inline"><mml:mrow><mml:msubsup><mml:mrow><mml:mn>0.82</mml:mn></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>0.34</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.28</mml:mn></mml:mrow></mml:msubsup></mml:mrow></mml:math></inline-formula>. The inferred rate of mergers similar to GW190521 is <inline-formula><mml:math display="inline"><mml:mrow><mml:msubsup><mml:mrow><mml:mn>0.13</mml:mn></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>0.11</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.30</mml:mn></mml:mrow></mml:msubsup><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:msup><mml:mrow><mml:mi>Gpc</mml:mi></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>3</mml:mn></mml:mrow></mml:msup><mml:mtext> </mml:mtext><mml:msup><mml:mrow><mml:mi>yr</mml:mi></mml:mrow><mml:mrow><mml:mo>-</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math></inline-formula>.

[]

https://arxiv.org/pdf/2009.01075.pdf

2003MNRAS.345.1057M

A Fundamental Plane of black hole activity

2003-01-01

['accretion', 'accretion disks', 'black hole physics', 'galaxies active', 'astronomy radio', 'astronomy x rays', 'astronomy x rays', 'astrophysics']

[]

We examine the disc-jet connection in stellar mass and supermassive black holes by investigating the properties of their compact emission in the X-ray and radio bands. We compile a sample of ~100 active galactic nuclei with measured masses, 5-GHz core emission, and 2-10 keV luminosities, together with eight galactic black holes with a total of ~50 simultaneous observations in the radio and X-ray bands. Using this sample, we study the correlations between the radio (L<SUB>R</SUB>) and the X-ray (L<SUB>X</SUB>) luminosity and the black hole mass (M). We find that the radio luminosity is correlated with bothM and L<SUB>X</SUB>, at a highly significant level. In particular, we show that the sources define a `Fundamental Plane' in the three-dimensional (logL<SUB>R</SUB>, logL<SUB>X</SUB>, logM) space, given by logL<SUB>R</SUB>= (0.60<SUP>+0.11</SUP><SUB>-0.11</SUB>) logL<SUB>X</SUB>+ (0.78<SUP>+0.11</SUP><SUB>-0.09</SUB>) logM+ 7.33<SUP>+4.05</SUP><SUB>-4.07</SUB>, with a substantial scatter of σ<SUB>R</SUB>= 0.88. We compare our results to the theoretical relations between radio flux, black hole mass, and accretion rate derived by Heinz &amp; Sunyaev. Such relations depend only on the assumed accretion model and on the observed radio spectral index. Therefore, we are able to show that the X-ray emission from black holes accreting at less than a few per cent of the Eddington rate is unlikely to be produced by radiatively efficient accretion, and is marginally consistent with optically thin synchrotron emission from the jet. On the other hand, models for radiatively inefficient accretion flows seem to agree well with the data.

[]

https://arxiv.org/pdf/astro-ph/0305261.pdf

2006PhRvL..96k1102B

Gravitational-Wave Extraction from an Inspiraling Configuration of Merging Black Holes

2006-01-01

['-', '-', '-', '-', 'methods numerical', 'waves', '-', '-', '-', 'astrophysics', '-']

[]

We present new ideas for evolving black holes through a computational grid without excision, which enable accurate and stable evolutions of binary black hole systems with the accurate determination of gravitational waveforms directly from the wave zone region. Rather than excising the black hole interiors, our approach follows the “puncture” treatment of black holes, but utilizing a new gauge condition which allows the black holes to move successfully through the computational domain. We apply these techniques to an inspiraling binary, modeling the radiation generated during the final plunge and ringdown. We demonstrate convergence of the waveforms and good conservation of mass-energy, with just over 3% of the system’s mass converted to gravitational radiation.

[]

https://arxiv.org/pdf/gr-qc/0511103.pdf

2012JHEP...07..033K

P - V criticality of charged AdS black holes

2012-01-01

['-', 'black hole physics', '-', '-']

[]

Treating the cosmological constant as a thermodynamic pressure and its conjugate quantity as a thermodynamic volume, we reconsider the critical behaviour of charged AdS black holes. We complete the analogy of this system with the liquid-gas system and study its critical point, which occurs at the point of divergence of specific heat at constant pressure. We calculate the critical exponents and show that they coincide with those of the Van der Waals system.

[]

https://arxiv.org/pdf/1205.0559.pdf

2008MNRAS.391..481S

A semi-analytic model for the co-evolution of galaxies, black holes and active galactic nuclei

2008-01-01

['galaxies evolution', 'galaxies formation', 'cosmology theory', 'astrophysics']

[]

We present a new semi-analytic model that self-consistently traces the growth of supermassive black holes (BH) and their host galaxies within the context of the Lambda cold dark matter (ΛCDM) cosmological framework. In our model, the energy emitted by accreting black holes regulates the growth of the black holes themselves, drives galactic scale winds that can remove cold gas from galaxies, and produces powerful jets that heat the hot gas atmospheres surrounding groups and clusters. We present a comprehensive comparison of our model predictions with observational measurements of key physical properties of low-redshift galaxies, such as cold gas fractions, stellar metallicities and ages, and specific star formation rates. We find that our new models successfully reproduce the exponential cut-off in the stellar mass function and the stellar and cold gas mass densities at z ~ 0, and predict that star formation should be largely, but not entirely, quenched in massive galaxies at the present day. We also find that our model of self-regulated BH growth naturally reproduces the observed relation between BH mass and bulge mass. We explore the global formation history of galaxies and black holes in our models, presenting predictions for the cosmic histories of star formation, stellar mass assembly, cold gas and metals. We find that models assuming the `concordance' ΛCDM cosmology overproduce star formation and stellar mass at high redshift (z &gt;~ 2). A model with less small-scale power predicts less star formation at high redshift, and excellent agreement with the observed stellar mass assembly history, but may have difficulty accounting for the cold gas in quasar absorption systems at high redshift (z ~ 3-4).

[]

https://arxiv.org/pdf/0808.1227.pdf

1993PhRvL..70.2837G

Black strings and p-branes are unstable

1993-01-01

['black hole physics', 'gravitation', 'perturbation theory', 'quantum theory', 'relativity', 'string theory', 'angular momentum', 'thermodynamics', 'quantum theory', 'quantum theory', '-', '-', '-', '-', '-', 'black hole physics', '-', '-', '-']

[]

We investigate the evolution of small perturbations around black strings and branes which are low energy solutions of string theory. For simplicity we focus attention on the zero charge case and show that there are unstable modes for a range of time frequency and wavelength in the extra 10-D dimensions. These perturbations can be stabilized if the extra dimensions are compactified to a scale smaller than the minimum wavelength for which instability occurs and thus will not affect large astrophysical black holes in four dimensions. We comment on the implications of this result for the cosmic censorship hypothesis.

[]

https://arxiv.org/pdf/hep-th/9301052.pdf

2006PhRvL..96c1103H

Formation and Evaporation of Nonsingular Black Holes

2006-01-01

['-', '-', '-', '-']

[]

Regular (nonsingular) space-times are given that describe the formation of a (locally defined) black hole from an initial vacuum region, its quiescence as a static region, and its subsequent evaporation to a vacuum region. The static region is Bardeen-like, supported by finite density and pressures, vanishing rapidly at large radius and behaving as a cosmological constant at small radius. The dynamic regions are Vaidya-like, with ingoing radiation of positive-energy flux during collapse and negative-energy flux during evaporation, the latter balanced by outgoing radiation of positive-energy flux and a surface pressure at a pair creation surface. The black hole consists of a compact space-time region of trapped surfaces, with inner and outer boundaries that join circularly as a single smooth trapping horizon.

[]

https://arxiv.org/pdf/gr-qc/0506126.pdf

2010RvMP...82.3121G

The Galactic Center massive black hole and nuclear star cluster

2010-01-01

['-', '-', '-']

[]

The Galactic Center is an excellent laboratory for studying phenomena and physical processes that may be occurring in many other galactic nuclei. The center of our Milky Way is by far the closest galactic nucleus, and observations with exquisite resolution and sensitivity cover 18 orders of magnitude in energy of electromagnetic radiation. Theoretical simulations have become increasingly more powerful in explaining these measurements. This review summarizes the recent progress in observational and theoretical work on the central parsec, with a strong emphasis on the current empirical evidence for a central massive black hole and on the processes in the surrounding dense nuclear star cluster. Current evidence is presented, from the analysis of the orbits of more than two dozen stars and from the measurements of the size and motion of the central compact radio source, Sgr A* , that this radio source must be a massive black hole of about 4.4×10<SUP>6</SUP>M<SUB>⊙</SUB> , beyond any reasonable doubt. What is known about the structure and evolution of the dense nuclear star cluster surrounding this black hole is reported, including the astounding fact that stars have been forming in the vicinity of Sgr A* recently, apparently with a top-heavy stellar-mass function. A dense concentration of fainter stars centered in the immediate vicinity of the massive black hole are discussed, three of which have orbital peri-bothroi of less than one light day. This “S-star cluster” appears to consist mainly of young early-type stars, in contrast to the predicted properties of an equilibrium “stellar cusp” around a black hole. This constitutes a remarkable and presently not fully understood “paradox of youth.” What is known about the emission properties of the accreting gas onto Sgr A* is also summarized and how this emission is beginning to delineate the physical properties in the hot accretion zone around the event horizon.

[]

https://arxiv.org/pdf/1006.0064.pdf

2010PhRvD..81j4019C

New cosmological constraints on primordial black holes

2010-01-01

['-', '-', '-', '-', '-', 'cosmology dark matter', 'black hole physics', 'particles', '-', '-', '-', '-']

[]

We update the constraints on the fraction of the Universe going into primordial black holes in the mass range 10<SUP>9</SUP>-10<SUP>17</SUP>g associated with the effects of their evaporations on big bang nucleosynthesis and the extragalactic photon background. We include for the first time all the effects of quark and gluon emission by black holes on these constraints and account for the latest observational developments. We then discuss the other constraints in this mass range and show that these are weaker than the nucleosynthesis and photon background limits, apart from a small range 10<SUP>13</SUP>-10<SUP>14</SUP>g, where the damping of cosmic microwave background anisotropies dominates. Finally we review the gravitational and astrophysical effects of nonevaporating primordial black holes, updating constraints over the broader mass range 1-10<SUP>50</SUP>g.

[]

https://arxiv.org/pdf/0912.5297.pdf

2017MNRAS.465.3291W

Simulating galaxy formation with black hole driven thermal and kinetic feedback

2017-01-01

['black hole physics', 'methods numerical', 'galaxies clusters', 'galaxies evolution', 'galaxies formation', 'cosmology theory', '-']

[]

The inefficiency of star formation in massive elliptical galaxies is widely believed to be caused by the interactions of an active galactic nucleus (AGN) with the surrounding gas. Achieving a sufficiently rapid reddening of moderately massive galaxies without expelling too many baryons has however proven difficult for hydrodynamical simulations of galaxy formation, prompting us to explore a new model for the accretion and feedback effects of supermassive black holes. For high-accretion rates relative to the Eddington limit, we assume that a fraction of the accreted rest mass energy heats the surrounding gas thermally, similar to the 'quasar mode' in previous work. For low-accretion rates, we invoke a new, pure kinetic feedback model that imparts momentum to the surrounding gas in a stochastic manner. These two modes of feedback are motivated both by theoretical conjectures for the existence of different types of accretion flows as well as recent observational evidence for the importance of kinetic AGN winds in quenching galaxies. We find that a large fraction of the injected kinetic energy in this mode thermalizes via shocks in the surrounding gas, thereby providing a distributed heating channel. In cosmological simulations, the resulting model produces red, non-star-forming massive elliptical galaxies, and achieves realistic gas fractions, black hole growth histories and thermodynamic profiles in large haloes.

[]

https://arxiv.org/pdf/1607.03486.pdf

2007JHEP...09..120H

Black holes as mirrors: quantum information in random subsystems

2007-01-01

['-', '-', '-']

[]

We study information retrieval from evaporating black holes, assuming that the internal dynamics of a black hole is unitary and rapidly mixing, and assuming that the retriever has unlimited control over the emitted Hawking radiation. If the evaporation of the black hole has already proceeded past the ``half-way'' point, where half of the initial entropy has been radiated away, then additional quantum information deposited in the black hole is revealed in the Hawking radiation very rapidly. Information deposited prior to the half-way point remains concealed until the half-way point, and then emerges quickly. These conclusions hold because typical local quantum circuits are efficient encoders for quantum error-correcting codes that nearly achieve the capacity of the quantum erasure channel. Our estimate of a black hole's information retention time, based on speculative dynamical assumptions, is just barely compatible with the black hole complementarity hypothesis.

[]

https://arxiv.org/pdf/0708.4025.pdf

1993PhRvD..48.3743S

The stretched horizon and black hole complementarity

1993-01-01

['-', '-', 'black hole physics', '-', '-']

[]

Three postulates asserting the validity of conventional quantum theory, semiclassical general relativity, and the statistical basis for thermodynamics are introduced as a foundation for the study of black-hole evolution. We explain how these postulates may be implemented in a ``stretched horizon'' or membrane description of the black hole, appropriate to a distant observer. The technical analysis is illustrated in the simplified context of (1+1)-dimensional dilaton gravity. Our postulates imply that the dissipative properties of the stretched horizon arise from a course graining of microphysical degrees of freedom that the horizon must possess. A principle of black-hole complementarity is advocated. The overall viewpiont is similar to that poineered by 't Hooft but the detailed implementation is different.

[]

https://arxiv.org/pdf/hep-th/9306069.pdf

1998JHEP...02..009S

Black hole entropy from near-horizon microstates

1998-01-01

['-', '-']

[]

Black holes whose near-horizon geometries are locally, but not necessarily globally, AdS<SUB>3</SUB> (three-dimensional anti-de Sitter space) are considered. Using the fact that quantum gravity on AdS<SUB>3</SUB> is a conformal field theory, we microscopically compute the black hole entropy from the asymptotic growth of states. Precise numerical agreement with the Bekenstein-Hawking area formula for the entropy is found. The result pertains to any consistent quantum theory of gravity, and does not use string theory or supersymmetry.

[]

https://arxiv.org/pdf/hep-th/9712251.pdf

2021RPPh...84k6902C

Constraints on primordial black holes

2021-01-01

['-', 'cosmology dark matter', '-', 'cosmology early universe', '-', '-', '-', '-']

[]

We update the constraints on the fraction of the Universe that may have gone into primordial black holes (PBHs) over the mass range 10<SUP>-5</SUP> to 10<SUP>50</SUP> g. Those smaller than ~10<SUP>15</SUP> g would have evaporated by now due to Hawking radiation, so their abundance at formation is constrained by the effects of evaporated particles on big bang nucleosynthesis, the cosmic microwave background (CMB), the Galactic and extragalactic γ-ray and cosmic ray backgrounds and the possible generation of stable Planck mass relics. PBHs larger than ~10<SUP>15</SUP> g are subject to a variety of constraints associated with gravitational lensing, dynamical effects, influence on large-scale structure, accretion and gravitational waves. We discuss the constraints on both the initial collapse fraction and the current fraction of the dark matter (DM) in PBHs at each mass scale but stress that many of the constraints are associated with observational or theoretical uncertainties. We also consider indirect constraints associated with the amplitude of the primordial density fluctuations, such as second-order tensor perturbations and μ-distortions arising from the effect of acoustic reheating on the CMB, if PBHs are created from the high-σ peaks of nearly Gaussian fluctuations. Finally we discuss how the constraints are modified if the PBHs have an extended mass function, this being relevant if PBHs provide some combination of the DM, the LIGO/Virgo coalescences and the seeds for cosmic structure. Even if PBHs make a small contribution to the DM, they could play an important cosmological role and provide a unique probe of the early Universe.

[]

https://arxiv.org/pdf/2002.12778.pdf

2008PhRvD..78f5034G

Breaking an Abelian gauge symmetry near a black hole horizon

2008-01-01

['-', '-', '-', '-', '-', '-', '-']

[]

I argue that coupling the Abelian Higgs model to gravity plus a negative cosmological constant leads to black holes which spontaneously break the gauge invariance via a charged scalar condensate slightly outside their horizon. This suggests that black holes can superconduct.

[]

https://arxiv.org/pdf/0801.2977.pdf

2005ApJ...618..569M

On the Maximum Luminosity of Galaxies and Their Central Black Holes: Feedback from Momentum-driven Winds

2005-01-01

['galaxies formation', 'galaxies fundamental parameters', 'galaxies general', 'galaxies starburst', 'galaxies intergalactic medium', 'astrophysics']

[]

We investigate large-scale galactic winds driven by momentum deposition. Momentum injection is provided by (1) radiation pressure produced by the continuum absorption and scattering of photons on dust grains and (2) supernovae (momentum injection by supernovae is important even if the supernova energy is radiated away). Radiation can be produced by a starburst or active galactic nucleus (AGN) activity. We argue that momentum-driven winds are an efficient mechanism for feedback during the formation of galaxies. We show that above a limiting luminosity, momentum deposition from star formation can expel a significant fraction of the gas in a galaxy. The limiting, Eddington-like luminosity is L<SUB>M</SUB>~=(4f<SUB>g</SUB>c/G)σ<SUP>4</SUP>, where σ is the galaxy velocity dispersion and f<SUB>g</SUB> is the gas fraction; the subscript M refers to momentum driving. A starburst that attains L<SUB>M</SUB> moderates its star formation rate and its luminosity does not increase significantly further. We argue that elliptical galaxies attain this limit during their growth at z&gt;~1 and that this is the origin of the Faber-Jackson relation. We show that Lyman break galaxies and ultraluminous infrared galaxies have luminosities near L<SUB>M</SUB>. Since these starbursting galaxies account for a significant fraction of the star formation at z&gt;~1, this supports our hypothesis that much of the observed stellar mass in early-type galaxies was formed during Eddington-limited star formation. Star formation is unlikely to efficiently remove gas from very small scales in galactic nuclei, i.e., scales much smaller than that of a nuclear starburst. This gas is available to fuel a central black hole (BH). We argue that a BH clears gas out of its galactic nucleus when the luminosity of the BH itself reaches ~L<SUB>M</SUB>. This shuts off the fuel supply to the BH and may also terminate star formation in the surrounding galaxy. As a result, the BH mass is fixed to be M<SUB>BH</SUB>~=(f<SUB>g</SUB>κ<SUB>es</SUB>/πG<SUP>2</SUP>)σ<SUP>4</SUP>, where κ<SUB>es</SUB> is the electron scattering opacity. This limit is in accord with the observed M<SUB>BH</SUB>-σ relation.

[]

https://arxiv.org/pdf/astro-ph/0406070.pdf

2014ARA&A..52..589H

The Coevolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe

2014-01-01

['-', '-', '-']

[]

We summarize what large surveys of the contemporary Universe have taught us about the physics and phenomenology of the processes that link the formation and evolution of galaxies with their central supermassive black holes. We present a picture in which the population of active galactic nuclei (AGNs) can be divided into two distinct populations. The radiative-mode AGNs are associated with black holes (BHs) that produce radiant energy powered by accretion at rates in excess of ∼1% of the Eddington limit. They are primarily associated with less massive BHs growing in high-density pseudobulges at a rate sufficient to produce the total mass budget in these BHs in ∼10 Gyr. The circumnuclear environment contains high-density cold gas and associated star formation. Major mergers are not the primary mechanism for transporting this gas inward; secular processes appear dominant. Stellar feedback is generic in these objects, and strong AGN feedback is seen only in the most powerful AGNs. In jet-mode AGNs the bulk of energetic output takes the form of collimated outflows (jets). These AGNs are associated with the more massive BHs in more massive (classical) bulges and elliptical galaxies. Neither the accretion onto these BHs nor star formation in their host bulge is significant today. These AGNs are probably fueled by the accretion of slowly cooling hot gas that is limited by the feedback/heating provided by AGN radio sources. Surveys of the high-redshift Universe paint a similar picture. Noting that the volume-averaged ratio of star formation to BH growth has remained broadly constant over the past 10 Gyrs, we argue that the processes that linked the cosmic evolution of galaxies and BHs are still at play today.

[]

https://arxiv.org/pdf/1403.4620.pdf

2011MNRAS.418L..79T

Efficient generation of jets from magnetically arrested accretion on a rapidly spinning black hole

2011-01-01

['accretion', 'accretion disks', 'black hole physics', 'mhd', 'methods numerical', 'galaxies jets', '-', '-']

[]

We describe global, 3D, time-dependent, non-radiative, general-relativistic, magnetohydrodynamic simulations of accreting black holes (BHs). The simulations are designed to transport a large amount of magnetic flux to the centre, more than the accreting gas can force into the BH. The excess magnetic flux remains outside the BH, impedes accretion, and leads to a magnetically arrested disc. We find powerful outflows. For a BH with spin parameter a = 0.5, the efficiency with which the accretion system generates outflowing energy in jets and winds is η≈ 30 per cent. For a = 0.99, we find η≈ 140 per cent, which means that more energy flows out of the BH than flows in. The only way this can happen is by extracting spin energy from the BH. Thus the a = 0.99 simulation represents an unambiguous demonstration, within an astrophysically plausible scenario, of the extraction of net energy from a spinning BH via the Penrose-Blandford-Znajek mechanism. We suggest that magnetically arrested accretion might explain observations of active galactic nuclei with apparent η≈ few × 100 per cent.

[]

https://arxiv.org/pdf/1108.0412.pdf

2018Natur.553..473B

An 800-million-solar-mass black hole in a significantly neutral Universe at a redshift of 7.5

2018-01-01

['-', '-']

[]

Quasars are the most luminous non-transient objects known and as a result they enable studies of the Universe at the earliest cosmic epochs. Despite extensive efforts, however, the quasar ULAS J1120 + 0641 at redshift z = 7.09 has remained the only one known at z &gt; 7 for more than half a decade. Here we report observations of the quasar ULAS J134208.10 + 092838.61 (hereafter J1342 + 0928) at redshift z = 7.54. This quasar has a bolometric luminosity of 4 × 10<SUP>13</SUP> times the luminosity of the Sun and a black-hole mass of 8 × 10<SUP>8</SUP> solar masses. The existence of this supermassive black hole when the Universe was only 690 million years old—just five per cent of its current age—reinforces models of early black-hole growth that allow black holes with initial masses of more than about 10<SUP>4</SUP> solar masses or episodic hyper-Eddington accretion. We see strong evidence of absorption of the spectrum of the quasar redwards of the Lyman α emission line (the Gunn-Peterson damping wing), as would be expected if a significant amount (more than 10 per cent) of the hydrogen in the intergalactic medium surrounding J1342 + 0928 is neutral. We derive such a significant fraction of neutral hydrogen, although the exact fraction depends on the modelling. However, even in our most conservative analysis we find a fraction of more than 0.33 (0.11) at 68 per cent (95 per cent) probability, indicating that we are probing well within the reionization epoch of the Universe.

[]

https://arxiv.org/pdf/1712.01860.pdf

2016PhRvD..94h3504C

Primordial black holes as dark matter

2016-01-01

['-', '-']

[]

The possibility that the dark matter comprises primordial black holes (PBHs) is considered, with particular emphasis on the currently allowed mass windows at 1 0<SUP>16</SUP>- 1 0<SUP>17</SUP> g , 1 0<SUP>20</SUP>- 1 0<SUP>24</SUP> g and 1 - 1 0<SUP>3</SUP>M<SUB>⊙</SUB> . The Planck mass relics of smaller evaporating PBHs are also considered. All relevant constraints (lensing, dynamical, large-scale structure and accretion) are reviewed and various effects necessary for a precise calculation of the PBH abundance (non-Gaussianity, nonsphericity, critical collapse and merging) are accounted for. It is difficult to put all the dark matter in PBHs if their mass function is monochromatic but this is still possible if the mass function is extended, as expected in many scenarios. A novel procedure for confronting observational constraints with an extended PBH mass spectrum is therefore introduced. This applies for arbitrary constraints and a wide range of PBH formation models and allows us to identify which model-independent conclusions can be drawn from constraints over all mass ranges. We focus particularly on PBHs generated by inflation, pointing out which effects in the formation process influence the mapping from the inflationary power spectrum to the PBH mass function. We then apply our scheme to two specific inflationary models in which PBHs provide the dark matter. The possibility that the dark matter is in intermediate-mass PBHs of 1 - 1 0<SUP>3</SUP>M<SUB>⊙</SUB> is of special interest in view of the recent detection of black-hole mergers by LIGO. The possibility of Planck relics is also intriguing but virtually untestable.

[]

https://arxiv.org/pdf/1607.06077.pdf

2003ApJ...582..559V

The Assembly and Merging History of Supermassive Black Holes in Hierarchical Models of Galaxy Formation

2003-01-01

['black hole physics', 'cosmology theory', 'galaxies evolution', 'galaxies quasars', 'astrophysics']

[]

We assess models for the assembly of supermassive black holes (SMBHs) at the center of galaxies that trace their hierarchical buildup far up in the dark halo ``merger tree.'' Motivated by the recent discovery of luminous quasars around redshift z~6-suggesting a very early assembly epoch-and by numerical simulations of the fragmentation of primordial molecular clouds in cold dark matter (CDM) cosmogonies, we assume that the first ``seed'' black holes (BHs) had intermediate masses and formed in (mini)halos collapsing at z~20 from high-σ density fluctuations. As these pregalactic holes become incorporated through a series of mergers into larger and larger halos, they sink to the center because of dynamical friction, accrete a fraction of the gas in the merger remnant to become supermassive, form a binary system, and eventually coalesce. The merger history of dark matter halos and associated BHs is followed by cosmological Monte Carlo realizations of the merger hierarchy from early times until the present in a ΛCDM cosmology. A simple model, where quasar activity is driven by major mergers and SMBHs accrete at the Eddington rate a mass that scales with the fifth power of the circular velocity of the host halo, is shown to reproduce the observed luminosity function of optically selected quasars in the redshift range 1&lt;z&lt;5. A scheme for describing the hardening of a BH binary in a stellar background with core formation due to mass ejection is applied, where the stellar cusp proportional to r<SUP>-2</SUP> is promptly regenerated after every major merger event, replenishing the mass displaced by the binary. Triple BH interactions will inevitably take place at early times if the formation route for the assembly of SMBHs goes back to the very first generation of stars, and we follow them in our merger tree. The assumptions underlying our scenario lead to the prediction of a population of massive BHs wandering in galaxy halos and the intergalactic medium at the present epoch and contributing &lt;~10% to the total BH mass density, ρ<SUB>SMBH</SUB>=4×10<SUP>5</SUP> M<SUB>solar</SUB> Mpc<SUP>-3</SUP> (h=0.7). The fraction of binary SMBHs in galaxy nuclei is on the order of 10% today, and it increases with redshift so that almost all massive nuclear BHs at early epochs are in binary systems. The fraction of binary quasars (both members brighter than 0.1L<SUB>*</SUB>) instead is less than 0.3% at all epochs. The nuclear SMBH occupation fraction is unity (0.6) at the present epoch if the first seed BHs were as numerous as the 3.5 σ (4 σ) density peaks at z=20.

[]

https://arxiv.org/pdf/astro-ph/0207276.pdf

2001PhRvL..87p1602D

Black Holes at the Large Hadron Collider

2001-01-01

['-', '-', '-']

[]

If the scale of quantum gravity is near TeV, the CERN Large Hadron Collider will be producing one black hole (BH) about every second. The decays of the BHs into the final states with prompt, hard photons, electrons, or muons provide a clean signature with low background. The correlation between the BH mass and its temperature, deduced from the energy spectrum of the decay products, can test Hawking's evaporation law and determine the number of large new dimensions and the scale of quantum gravity.

[]

https://arxiv.org/pdf/hep-ph/0106295.pdf

2002PhRvL..88j1101E

A Rotating Black Ring Solution in Five Dimensions

2002-01-01

['-', '-']

[]

The vacuum Einstein equations in five dimensions are shown to admit a solution describing a stationary asymptotically flat spacetime regular on and outside an event horizon of topology S<SUP>1</SUP>×S<SUP>2</SUP>. It describes a rotating ``black ring.'' This is the first example of a stationary asymptotically flat vacuum solution with an event horizon of nonspherical topology. The existence of this solution implies that the uniqueness theorems valid in four dimensions do not have simple five-dimensional generalizations. It is suggested that increasing the spin of a spherical black hole beyond a critical value results in a transition to a black ring, which can have an arbitrarily large angular momentum for a given mass.

[]

https://arxiv.org/pdf/hep-th/0110260.pdf

2002PhRvD..65e6010G

High energy colliders as black hole factories: The end of short distance physics

2002-01-01

['-', '-', '-', '-', '-', '-', '-', '-', '-', '-', '-', '-']

[]

If the fundamental Planck scale is of order of a TeV, as is the case in some extra-dimension scenarios, future hadron colliders such as the CERN Large Hadron Collider will be black hole factories. The nonperturbative process of black hole formation and decay by Hawking evaporation gives rise to spectacular events with up to many dozens of relatively hard jets and leptons with a characteristic ratio of hadronic to leptonic activity of roughly 5:1. The total transverse energy of such events is typically a sizable fraction of the beam energy. Perturbative hard scattering processes at energies well above the Planck scale are cloaked behind a horizon, thus limiting the ability to probe short distances. The high energy black hole cross section grows with energy at a rate determined by the dimensionality and geometry of the extra dimensions. This dependence therefore probes the extra dimensions at distances larger than the Planck scale.

[]

https://arxiv.org/pdf/hep-ph/0106219.pdf

1998PhRvL..80.5056A

Regular Black Hole in General Relativity Coupled to Nonlinear Electrodynamics

1998-01-01

['-', '-']

[]

The first regular exact black hole solution in general relativity is presented. The source is a nonlinear electrodynamic field satisfying the weak energy condition, which in the limit of weak field becomes the Maxwell field. The solution corresponds to a charged black hole with \|q\|&lt;=2s<SUB>c</SUB>m~0.6m, having the metric, the curvature invariants, and the electric field regular everywhere.

[]

https://arxiv.org/pdf/gr-qc/9911046.pdf

2002PhRvD..65h4014C

Gauss-Bonnet black holes in AdS spaces

2002-01-01

['-', '-', '-', '-', '-', 'black hole physics', '-', '-']

[]

We study the thermodynamic properties and phase structures of topological black holes in Einstein theory with a Gauss-Bonnet term and a negative cosmological constant. The event horizon of these topological black holes can be a hypersurface with positive, zero, or negative constant curvature. When the horizon is a zero curvature hypersurface, the thermodynamic properties of black holes are completely the same as those of black holes without the Gauss-Bonnet term, although the two black hole solutions are quite different. When the horizon is a negative constant curvature hypersurface, the thermodynamic properties of the Gauss-Bonnet black holes are qualitatively similar to those of black holes without the Gauss-Bonnet term. When the event horizon is a hypersurface with positive constant curvature, we find that the thermodynamic properties and phase structures of black holes drastically depend on the spacetime dimension d and the coefficient of the Gauss-Bonnet term: when d&gt;=6, the properties of black holes are also qualitatively similar to the case without the Gauss-Bonnet term, but when d=5, a new phase of locally stable small blacks holes occurs under a critical value of the Gauss-Bonnet coefficient, and beyond the critical value, the black holes are always thermodynamically stable. However, the locally stable small black hole is not globally preferred; instead a thermal anti-de Sitter space is globally preferred. We find that there is a minimal horizon radius, below which the Hawking-Page phase transition will not occur since for these black holes the thermal anti-de Sitter space is always globally preferred.

[]

https://arxiv.org/pdf/hep-th/0109133.pdf

1998PhRvL..80..904A

Quantum Geometry and Black Hole Entropy

1998-01-01

['-', '-']

[]

A ``black hole sector'' of nonperturbative canonical quantum gravity is introduced. The quantum black hole degrees of freedom are shown to be described by a Chern-Simons field theory on the horizon. It is shown that the entropy of a large nonrotating black hole is proportional to its horizon area. The constant of proportionality depends upon the Immirzi parameter, which fixes the spectrum of the area operator in loop quantum gravity; an appropriate choice of this parameter gives the Bekenstein-Hawking formula S = A/4l<SUP>2</SUP><SUB>P</SUB>. With the same choice of the Immirzi parameter, this result also holds for black holes carrying electric or dilatonic charge, which are not necessarily near extremal.

[]

https://arxiv.org/pdf/gr-qc/9710007.pdf

2000PhRvD..62h4003V

Schwarzschild black hole lensing

2000-01-01

['-', '-', '-', '-', '-', '-', 'black hole physics', '-', 'astrophysics', '-', '-']

[]

We study strong gravitational lensing due to a Schwarzschild black hole. Apart from the primary and the secondary images we find a sequence of images on both sides of the optic axis; we call them relativistic images. These images are formed due to large bending of light near r=3M (the closest distance of approach r<SUB>o</SUB> is greater than 3M). The sources of the entire universe are mapped in the vicinity of the black hole by these images. For the case of the Galactic supermassive ``black hole'' they are formed at about 17 microarcseconds from the optic axis. The relativistic images are not resolved among themselves, but they are resolved from the primary and secondary images. However the relativistic images are very much demagnified unless the observer, lens and source are very highly aligned. Because of this and some other difficulties the observation of these images does not seem to be feasible in the near future. However, it would be a great success of the general theory of relativity in a strong gravitational field if they ever were observed and it would also give an upper bound, r<SUB>o</SUB>=3.21M, to the compactness of the lens, which would support the black hole interpretation of the lensing object.

[]

https://arxiv.org/pdf/astro-ph/9904193.pdf

2016PhRvD..93d4007K

Frequency-domain gravitational waves from nonprecessing black-hole binaries. II. A phenomenological model for the advanced detector era

2016-01-01

['-']

[]

We present a new frequency-domain phenomenological model of the gravitational-wave signal from the inspiral, merger and ringdown of nonprecessing (aligned-spin) black-hole binaries. The model is calibrated to 19 hybrid effective-one-body-numerical-relativity waveforms up to mass ratios of 1 ∶18 and black-hole spins of |a /m |∼0.85 (0.98 for equal-mass systems). The inspiral part of the model consists of an extension of frequency-domain post-Newtonian expressions, using higher-order terms fit to the hybrids. The merger ringdown is based on a phenomenological ansatz that has been significantly improved over previous models. The model exhibits mismatches of typically less than 1% against all 19 calibration hybrids and an additional 29 verification hybrids, which provide strong evidence that, over the calibration region, the model is sufficiently accurate for all relevant gravitational-wave astronomy applications with the Advanced LIGO and Virgo detectors. Beyond the calibration region the model produces physically reasonable results, although we recommend caution in assuming that any merger-ringdown waveform model is accurate outside its calibration region. As an example, we note that an alternative nonprecessing model, SEOBNRv2 (calibrated up to spins of only 0.5 for unequal-mass systems), exhibits mismatch errors of up to 10% for high spins outside its calibration region. We conclude that waveform models would benefit most from a larger number of numerical-relativity simulations of high-aligned-spin unequal-mass binaries.

[]

https://arxiv.org/pdf/1508.07253.pdf

2002MNRAS.335..965Y

Observational constraints on growth of massive black holes

2002-01-01

['black hole physics', 'galaxies active', 'galaxies evolution', 'galaxies nuclei', 'galaxies quasars', 'cosmology miscellaneous', 'astrophysics']

[]

We study the observational constraints on the growth of massive black holes (BHs) in galactic nuclei. We use the velocity dispersions of early-type galaxies obtained by the Sloan Digital Sky Survey and the relation between BH mass and velocity dispersion to estimate the local BH mass density to be ρ<SUB>•</SUB>(z= 0) ~= (2.5 +/- 0.4) × 10<SUP>5</SUP>h<SUB>0.65</SUB><SUP>2</SUP>M<SUB>solar</SUB> Mpc<SUP>-3</SUP>. We also use the quasi-stellar object (QSO) luminosity function from the 2dF Redshift Survey to estimate the BH mass density accreted during optically bright QSO phases. The local BH mass density is consistent with the density accreted during optically bright QSO phases if QSOs have a mass-to-energy conversion efficiency ɛ~= 0.1. By studying the continuity equation for the BH mass distribution, including the effect of BH mergers, we find relations between the local BH mass function and the QSO luminosity function. If the BH mass is assumed to be conserved during BH mergers, comparison of the predicted relations with the observations suggests that luminous QSOs (L<SUB>bol</SUB>&gt;~ 10<SUP>46</SUP> erg s<SUP>-1</SUP>) have a high efficiency (e.g. ɛ~ 0.2, which is possible for thin-disc accretion on to a Kerr BH) and the growth of high-mass BHs (&gt;~10<SUP>8</SUP>M<SUB>solar</SUB>) comes mainly from accretion during optically bright QSO phases, or that luminous QSOs have a super-Eddington luminosity. If luminous QSOs are not accreting with super-Eddington luminosities and the growth of low-mass BHs also occurs mainly during optically bright QSO phases, less luminous QSOs must accrete with a low efficiency, &lt;0.1 alternatively, they may accrete with high efficiency, but a significant fraction should be obscured. We estimate that the mean lifetime of luminous QSOs (L<SUB>bol</SUB>&gt;~ 10<SUP>46</SUP> erg s<SUP>-1</SUP>) is (3-13) × 10<SUP>7</SUP> yr, which is comparable to the Salpeter time. We also investigate the case in which total BH mass decreases during BH mergers due to gravitational radiation; in the extreme case in which total BH entropy is conserved, the observations again suggest that BHs in most luminous QSOs are Kerr BHs accreting with an efficiency &gt;~0.1.

[]

https://arxiv.org/pdf/astro-ph/0203082.pdf

2000ApJ...528L..13F

Viewing the Shadow of the Black Hole at the Galactic Center

2000-01-01

['black hole physics', 'galaxies active', 'galaxy center', 'relativity', 'astronomy submillimeter', 'techniques interferometric', 'black hole physics', 'galaxies active', 'galaxy center', 'relativity', 'astronomy submillimeter', 'techniques interferometric', 'astrophysics']

[]

In recent years, evidence for the existence of an ultracompact concentration of dark mass associated with the radio source Sagittarius A* in the Galactic center has become very strong. However, unambiguous proof that this object is indeed a black hole is still lacking. A defining characteristic of a black hole is the event horizon. To a distant observer, the event horizon casts a relatively large ``shadow'' with an apparent diameter of ~10 gravitational radii that is due to the bending of light by the black hole, and this shadow is nearly independent of the black hole spin or orientation. The predicted size (~30 μas) of this shadow for Sgr A* approaches the resolution of current radio interferometers. If the black hole is maximally spinning and viewed edge-on, then the shadow will be offset by ~8 μas from the center of mass and will be slightly flattened on one side. Taking into account the scatter broadening of the image in the interstellar medium and the finite achievable telescope resolution, we show that the shadow of Sgr A* may be observable with very long baseline interferometry at submillimeter wavelengths, assuming that the accretion flow is optically thin in this region of the spectrum. Hence, there exists a realistic expectation of imaging the event horizon of a black hole within the next few years.

[]

https://arxiv.org/pdf/astro-ph/9912263.pdf

2006csxs.book..157M

Black hole binaries

2006-01-01

['black hole physics', 'astronomy x rays', 'astrophysics']

[]

We review the properties of 40 X-ray binaries that contain either a confirmed black hole or a black hole candidate. After discussing briefly the significance of these Galactic black holes to both astronomy and physics, we present basic data for all 40 systems, review the physics of mass accretion onto black holes, and then show seven-year light curves of 20 systems. The second half of this work is a far-reaching review of the canonical emission states of black hole binaries, which is based on X-ray, radio and gamma-ray data. For several selected black holes, we show 33 pairs of X-ray energy and power density spectra and use these spectra as a basis for introducing modified definitions of the canonical X-ray emission states of an accreting black hole. We highlight the physical structures and some of the emission mechanisms associated with each emission state. In the final pages we examine both low- and high-frequency quasi-periodic oscillations. A recurring theme of the review is the importance of these black holes as potential sites for tests of general relativity. Accordingly, we stress phenomena that originate in strong gravity, such as relativistic Fe emission lines and thermal continuum emission, both of which arise in the inner accretion disk. Especially important in this regard are the high-frequency (40-450 Hz) quasi-periodic oscillations observed for seven black holes, three of which show evidence for commensurate (3:2) pairs of frequencies.

[]

https://arxiv.org/pdf/astro-ph/0306213.pdf

2001ApJ...551L..27M

Massive Black Holes as Population III Remnants

2001-01-01

['black hole physics', 'cosmology theory', 'cosmology early universe', 'galaxies formation', 'astrophysics']

[]

Recent numerical simulations of the fragmentation of primordial molecular clouds in hierarchical cosmogonies have suggested that the very first stars (the so-called Population III) may have been rather massive. Here we point out that a numerous population of massive black holes (MBHs)-with masses intermediate between those of stellar and supermassive holes-may be the end product of such an episode of pregalactic star formation. If only one MBH with m<SUB>•</SUB>&gt;~150 M<SUB>solar</SUB> formed in each of the ``minihalos'' collapsing at z~20 from 3 σ fluctuations, then the mass density of Population III MBHs would be comparable to that of the supermassive variety observed in the nuclei of galaxies. Since they form in high-σ rare density peaks, relic MBHs are predicted to cluster in the bulges of present-day galaxies as they become incorporated through a series of mergers into larger and larger systems. Dynamical friction would cause &gt;~50 (m<SUB>•</SUB>/150 M<SUB>solar</SUB>)<SUP>1/2</SUP> such objects to sink toward the center. The presence of a small cluster of MBHs in galaxy nuclei may have several interesting consequences associated with it, such as tidal captures of ordinary stars (likely followed by disruption), MBH capture by the central supermassive black hole, and gravitational wave radiation from such coalescences. Accreting pregalactic MBHs may be detectable as ultraluminous, off-nuclear X-ray sources.

[]

https://arxiv.org/pdf/astro-ph/0101223.pdf

2005ForPh..53..793M

The fuzzball proposal for black holes: an elementary review

2005-01-01

['-', '-']

[]

We give an elementary review of black holes in string theory. We discuss BPS holes, the microscopic computation of entropy and the 'fuzzball' picture of the black hole interior suggested by microstates of the 2-charge system.

[]

https://arxiv.org/pdf/hep-th/0502050.pdf

1993PhRvL..71.3743P

Information in black hole radiation

1993-01-01

['-', '-', 'black hole physics', '-', '-']

[]

If black hole formation evaporation can be described by an S matrix, information would be expected to come out in black hole radiation. An estimate shows that it may come out initially so slowly, or else be so spread out, that it would never show up in an analysis perturbative in M<SUB>Planck</SUB>/M, or in 1/N for two-dimensional dilatonic black holes with a large number N of minimally coupled scalar fields.

[]

https://arxiv.org/pdf/hep-th/9306083.pdf

1995PhRvD..52.5412F

N=2 extremal black holes

1995-01-01

['-', '-', '-', '-', '-', '-', '-', '-']

[]

It is shown that extremal magnetic black hole solutions of N=2 supergravity coupled to vector multiplets X<SUP>Λ</SUP> with a generic holomorphic prepotential F(X<SUP>Λ</SUP>) can be described as supersymmetric solitons which interpolate between maximally symmetric limiting solutions at spatial infinity and the horizon. A simple exact solution is found for the special case that the ratios of the X<SUP>Λ</SUP> are real, and it is seen that the logarithm of the conformal factor of the spatial metric equals the Kähler potential on the vector multiplet moduli space. Several examples are discussed in detail.

[]

https://arxiv.org/pdf/hep-th/9508072.pdf

2016PhRvL.116x1102A

Properties of the Binary Black Hole Merger GW150914

2016-01-01

['-', '-']

[]

On September 14, 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected a gravitational-wave transient (GW150914); we characterize the properties of the source and its parameters. The data around the time of the event were analyzed coherently across the LIGO network using a suite of accurate waveform models that describe gravitational waves from a compact binary system in general relativity. GW150914 was produced by a nearly equal mass binary black hole of masses 3 6<SUB>-4</SUB><SUP>+5</SUP>M<SUB>⊙</SUB> and 2 9<SUB>-4</SUB><SUP>+4</SUP>M<SUB>⊙</SUB> ; for each parameter we report the median value and the range of the 90% credible interval. The dimensionless spin magnitude of the more massive black hole is bound to be &lt;0.7 (at 90% probability). The luminosity distance to the source is 41 0<SUB>-180</SUB><SUP>+160</SUP> Mpc , corresponding to a redshift 0.0 9<SUB>-0.04</SUB><SUP>+0.03</SUP> assuming standard cosmology. The source location is constrained to an annulus section of 610 deg<SUP>2</SUP> , primarily in the southern hemisphere. The binary merges into a black hole of mass 6 2<SUB>-4</SUB><SUP>+4</SUP>M<SUB>⊙</SUB> and spin 0.6 7<SUB>-0.07</SUB><SUP>+0.05</SUP>. This black hole is significantly more massive than any other inferred from electromagnetic observations in the stellar-mass regime.

[]

https://arxiv.org/pdf/1602.03840.pdf

2005SSRv..116..523F

Supermassive Black Holes in Galactic Nuclei: Past, Present and Future Research

2005-01-01

['astrophysics']

[]

This review discusses the current status of supermassive black hole research, as seen from a purely observational standpoint. Since the early ‘90s, rapid technological advances, most notably the launch of the Hubble Space Telescope, the commissioning of the VLBA and improvements in near-infrared speckle imaging techniques, have not only given us incontrovertible proof of the existence of supermassive black holes, but have unveiled fundamental connections between the mass of the central singularity and the global properties of the host galaxy. It is thanks to these observations that we are now, for the first time, in a position to understand the origin, evolution and cosmic relevance of these fascinating objects.

[]

https://arxiv.org/pdf/astro-ph/0411247.pdf

2016PhRvL.117f1101S

Primordial Black Hole Scenario for the Gravitational-Wave Event GW150914

2016-01-01

['-', '-']

[]

We point out that the gravitational-wave event GW150914 observed by the LIGO detectors can be explained by the coalescence of primordial black holes (PBHs). It is found that the expected PBH merger rate would exceed the rate estimated by the LIGO Scientific Collaboration and the Virgo Collaboration if PBHs were the dominant component of dark matter, while it can be made compatible if PBHs constitute a fraction of dark matter. Intriguingly, the abundance of PBHs required to explain the suggested lower bound on the event rate, &gt;2 events Gpc<SUP>-3</SUP> yr<SUP>-1</SUP> , roughly coincides with the existing upper limit set by the nondetection of the cosmic microwave background spectral distortion. This implies that the proposed PBH scenario may be tested in the not-too-distant future.

[]

https://arxiv.org/pdf/1603.08338.pdf

2019ApJ...882L..24A

Binary Black Hole Population Properties Inferred from the First and Second Observing Runs of Advanced LIGO and Advanced Virgo

2019-01-01

['black hole physics', 'gravitational waves', 'methods statistical', '-']

[]

We present results on the mass, spin, and redshift distributions with phenomenological population models using the 10 binary black hole (BBH) mergers detected in the first and second observing runs completed by Advanced LIGO and Advanced Virgo. We constrain properties of the BBH mass spectrum using models with a range of parameterizations of the BBH mass and spin distributions. We find that the mass distribution of the more massive BH in such binaries is well approximated by models with no more than 1% of BHs more massive than 45 {M}<SUB>⊙ </SUB> and a power-law index of α = {1.3}<SUB>-1.7</SUB><SUP>+1.4</SUP> (90% credibility). We also show that BBHs are unlikely to be composed of BHs with large spins aligned to the orbital angular momentum. Modeling the evolution of the BBH merger rate with redshift, we show that it is flat or increasing with redshift with 93% probability. Marginalizing over uncertainties in the BBH population, we find robust estimates of the BBH merger rate density of R = {53.2}<SUB>-28.2</SUB><SUP>+55.8</SUP> Gpc<SUP>-3</SUP> yr<SUP>-1</SUP> (90% credibility). As the BBH catalog grows in future observing runs, we expect that uncertainties in the population model parameters will shrink, potentially providing insights into the formation of BHs via supernovae, binary interactions of massive stars, stellar cluster dynamics, and the formation history of BHs across cosmic time.

[]

https://arxiv.org/pdf/1811.12940.pdf

2000PhRvD..62b4027H

Quasinormal modes of AdS black holes and the approach to thermal equilibrium

2000-01-01

['-', '-', '-', '-', '-', '-', '-', '-', '-', '-', '-']

[]

We investigate the decay of a scalar field outside a Schwarzschild anti-de Sitter black hole. This is determined by computing the complex frequencies associated with quasinormal modes. There are qualitative differences from the asymptotically flat case, even in the limit of small black holes. In particular, for a given angular dependence, the decay is always exponential-there are no power law tails at late times. In terms of the AdS-CFT correspondence, a large black hole corresponds to an approximately thermal state in the field theory, and the decay of the scalar field corresponds to the decay of a perturbation of this state. Thus one obtains the time scale for the approach to thermal equilibrium. We compute these time scales for the strongly coupled field theories in three, four, and six dimensions, which are dual to string theory in asymptotically AdS spacetimes.

[]

https://arxiv.org/pdf/hep-th/9909056.pdf

2000CQGra..17..399C

Thermodynamics of Kerr-Newman-AdS black holes and conformal field theories

2000-01-01

['-', '-']

[]

We study the thermodynamics of four-dimensional Kerr-Newman-AdS black holes both in the canonical and the grand-canonical ensemble. The stability conditions are investigated, and the complete phase diagrams are obtained, which include the Hawking-Page phase transition in the grand-canonical ensemble. In the canonical case, one has a first order transition between small and large black holes, which disappears for sufficiently large electric charge or angular momentum. This disappearance corresponds to a critical point in the phase diagram. Via the AdS/CFT conjecture, the obtained phase structure is also relevant for the corresponding conformal field theory living in a rotating Einstein universe, in the presence of a global background U(1) current. An interesting limit arises when the black holes preserve some supersymmetry. These BPS black holes correspond to highly degenerate zero temperature states in the dual CFT, which lives in an Einstein universe rotating with the speed of light.

[]

https://arxiv.org/pdf/hep-th/9908022.pdf

2019MNRAS.486.2827D

SIMBA: Cosmological simulations with black hole growth and feedback

2019-01-01

['galaxies evolution', 'galaxies formation', '-', '-']

[]

We introduce the SIMBA simulations, the next generation of the MUFASA cosmological galaxy formation simulations run with GIZMO's meshless finite mass hydrodynamics. SIMBA includes updates to MUFASA's sub-resolution star formation and feedback prescriptions, and introduces black hole growth via the torque-limited accretion model of Anglés-Alcázar et al. from cold gas and Bondi accretion from hot gas, along with black hole feedback via kinetic bipolar outflows and X-ray energy. Ejection velocities are taken to be {∼ } 10^3 km s^{-1} at high Eddington ratios, increasing to {∼ } 8000 km s^{-1} at Eddington ratios below 2 per cent, with a constant momentum input of 20L/c. SIMBA further includes an on-the-fly dust production, growth, and destruction model. Our SIMBA run with (100h^{-1} Mpc)^3 and 1024<SUP>3</SUP> gas elements reproduces numerous observables, including galaxy stellar mass functions at z = 0-6, the stellar mass-star formation rate main sequence, H I and H<SUB>2</SUB> fractions, the mass-metallicity relation at z ≈ 0, 2, star-forming galaxy sizes, hot gas fractions in massive haloes, and z = 0 galaxy dust properties. However, SIMBA also yields an insufficiently sharp truncation of the z = 0 mass function, and too-large sizes for low-mass quenched galaxies. We show that SIMBA's jet feedback is primarily responsible for quenching massive galaxies.

[]

https://arxiv.org/pdf/1901.10203.pdf

2002Natur.419..694S

A star in a 15.2-year orbit around the supermassive black hole at the centre of the Milky Way

2002-01-01

['astrophysics']

[]

Many galaxies are thought to have supermassive black holes at their centres-more than a million times the mass of the Sun. Measurements of stellar velocities and the discovery of variable X-ray emission have provided strong evidence in favour of such a black hole at the centre of the Milky Way, but have hitherto been unable to rule out conclusively the presence of alternative concentrations of mass. Here we report ten years of high-resolution astrometric imaging that allows us to trace two-thirds of the orbit of the star currently closest to the compact radio source (and massive black-hole candidate) Sagittarius A*. The observations, which include both pericentre and apocentre passages, show that the star is on a bound, highly elliptical keplerian orbit around Sgr A*, with an orbital period of 15.2 years and a pericentre distance of only 17 light hours. The orbit with the best fit to the observations requires a central point mass of (3.7 +/- 1.5) × 10<SUP>6</SUP> solar masses (M<SUB></SUB>). The data no longer allow for a central mass composed of a dense cluster of dark stellar objects or a ball of massive, degenerate fermions.

[]

https://arxiv.org/pdf/astro-ph/0210426.pdf

1999PhRvD..60j4026C

Holography, thermodynamics, and fluctuations of charged AdS black holes

1999-01-01

['-', '-', '-', '-', '-', '-']

[]

The physical properties of Reissner-Nordström black holes in (n+1)-dimensional anti-de Sitter spacetime are related, by a holographic map, to the physics of a class of n-dimensional field theories coupled to a background global current. Motivated by that fact, and the recent observations of the striking similarity between the thermodynamic phase structure of these black holes (in the canonical ensemble) and that of the van der Waals-Maxwell liquid-gas system, we explore the physics in more detail. We study fluctuations and stability within the equilibrium thermodynamics, examining the specific heats and electrical permittivity of the holes, and consider the analogue of the Clayperon equation at the phase boundaries. Consequently, we refine the phase diagrams in the canonical and grand canonical ensembles. We study the interesting physics in the neighborhood of the critical point in the canonical ensemble. There is a second order phase transition found there, and that region is characterized by a Landau-Ginzburg model with A<SUB>3</SUB> potential. The holographically dual field theories provide the description of the microscopic degrees of freedom which underlie all of the thermodynamics, as can be seen by examining the form of the microscopic fluctuations.

[]

https://arxiv.org/pdf/hep-th/9904197.pdf

2012MNRAS.423.3083M

General relativistic magnetohydrodynamic simulations of magnetically choked accretion flows around black holes

2012-01-01

['accretion', 'accretion disks', 'black hole physics', 'gravitation', 'hydrodynamics', 'mhd', 'methods numerical', '-', '-']

[]

Black hole (BH) accretion flows and jets are qualitatively affected by the presence of ordered magnetic fields. We study fully 3D global general relativistic magnetohydrodynamic (MHD) simulations of radially extended and thick (height H-to-cylindrical radius R ratio of |H/R| ∼ 0.2-1) accretion flows around BHs with various dimensionless spins (a/M, with BH mass M) and with initially toroidally dominated (φ-directed) and poloidally dominated (R-z directed) magnetic fields. First, for toroidal field models and BHs with high enough |a/M|, coherent large-scale (i.e. ≫H) dipolar poloidal magnetic flux patches emerge, thread the BH, and generate transient relativistic jets. Second, for poloidal field models, poloidal magnetic flux readily accretes through the disc from large radii and builds up to a natural saturation point near the BH. While models with |H/R| ∼ 1 and |a/M| ≤ 0.5 do not launch jets due to quenching by mass infall, for sufficiently high |a/M| or low |H/R| the polar magnetic field compresses the inflow into a geometrically thin highly non-axisymmetric 'magnetically choked accretion flow' (MCAF) within which the standard linear magnetorotational instability is suppressed. The condition of a highly magnetized state over most of the horizon is optimal for the Blandford-Znajek mechanism which generates persistent relativistic jets with ≳100 per cent efficiency for |a/M| ≳ 0.9. A magnetic Rayleigh-Taylor and Kelvin-Helmholtz unstable magnetospheric interface forms between the compressed inflow and bulging jet magnetosphere, which drives a new jet-disc quasi-periodic oscillation (JD-QPO) mechanism. The high-frequency QPO has spherical harmonic |m| = 1 mode period of τ∼ 70GM/c<SUP>3</SUP> for a/M∼ 0.9 with coherence quality factors Q≳ 10. Overall, our models are qualitatively distinct from most prior MHD simulations (typically, |H/R| ≪ 1 and poloidal flux is limited by initial conditions), so they should prove useful for testing accretion-jet theories and measuring a/M in systems such as SgrA* and M87.

[]

https://arxiv.org/pdf/1201.4163.pdf

2014NanoL..14.3347B

Fast and Broadband Photoresponse of Few-Layer Black Phosphorus Field-Effect Transistors

2014-01-01

['-', '-']

[]

Few-layer black phosphorus, a new elemental 2D material recently isolated by mechanical exfoliation, is a high-mobility layered semiconductor with a direct bandgap that is predicted to strongly depend on the number of layers, from 0.35 eV (bulk) to 2.0 eV (single-layer). Therefore, black phosphorus is an appealing candidate for tunable photodetection from the visible to the infrared part of the spectrum. We study the photoresponse of field-effect transistors (FETs) made of few-layer black phosphorus (3 nm to 8 nm thick), as a function of excitation wavelength, power and frequency. In the dark state, the black phosphorus FETs can be tuned both in hole and electron doping regimes allowing for ambipolar operation. We measure mobilities in the order of 100 cm2/V s and current ON/OFF ratio larger than 103. Upon illumination, the black phosphorus transistors show response to excitation wavelengths from the visible up to 940 nm and rise time of about 1 ms, demonstrating broadband and fast detection. The responsivity reaches 4.8 mA/W and it could be drastically enhanced by engineering a detector based on a PN junction. The ambipolar behavior coupled to the fast and broadband photodetection make few-layer black phosphorus a promising 2D material for photodetection across the visible and near-infrared part of the electromagnetic spectrum.

[]

https://arxiv.org/pdf/1403.0565.pdf