scholarly journals Black Hole Masses and Accretion Rates in Nearby AGN

2009 ◽  
Vol 5 (S267) ◽  
pp. 207-207
Author(s):  
Stuart Lumsden ◽  
Jonathan Digby-North ◽  
Olivia Jones ◽  
Hazel Rogers ◽  
Sam Rushforth ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Accretion Rates ◽  
Black Hole Masses

AbstractWe present results from a survey of the properties of the central black holes in nearby AGN. This shows that AGN radiating near Eddington are on average less massive now than at z ~ 1.

scholarly journals Uncertainties of the masses of black holes and Eddington ratios in AGN

2006 ◽  
Vol 2 (S238) ◽  
pp. 111-116
Author(s):  
Suzy Collin
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Reverberation Mapping ◽  
Line Region ◽  
Region I ◽  
Accretion Rates ◽  
Unknown Structure ◽  
The Masses ◽  
Empirical Size ◽  
Black Hole Masses

AbstractBlack hole masses in Active Galactic Nuclei have been determined in 35 objects through reverberation mapping of the emission line region. I mention some uncertainties of the method, such as the “scale factor” relating the Virial Product to the mass, which depends on the unknown structure and dynamics of the Broad Line Region.When the black hole masses are estimated indirectly using the empirical size-luminosity relation deduced from this method, the uncertainties can be larger, especially when the relation is extrapolated to high and low masses and/or luminosities. In particular they lead to Eddington ratiosof the order of unity in samples of Narrow Line Seyfert 1. As the optical-UV luminosity is provided by the accretion disk, the accretion rates can be determined and are found to be much larger than the Eddington rates.So, accretion must be performed at a super-critical rate through a slim disk, resulting in rapid growth of the black holes. The alternative is that the mass determination is wrong at this limit.

scholarly journals Toward Precision Measurement of Central Black Hole Masses

2009 ◽  
Vol 5 (S267) ◽  
pp. 151-160 ◽  
Author(s):  
Bradley M. Peterson
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Host Galaxy ◽  
Reverberation Mapping ◽  
Line Region ◽  
The Masses ◽  
The Relationship ◽  
Black Hole Masses ◽  
Intrinsic Scatter ◽  
Direct And Indirect Methods

AbstractWe review briefly direct and indirect methods of measuring the masses of black holes in galactic nuclei, and then focus attention on supermassive black holes in active nuclei, with special attention to results from reverberation mapping and their limitations. We find that the intrinsic scatter in the relationship between the AGN luminosity and the broad-line region size is very small, ~0.11 dex, comparable to the uncertainties in the better reverberation measurements. We also find that the relationship between reverberation-based black hole masses and host-galaxy bulge luminosities also seems to have surprisingly little intrinsic scatter, ~0.17 dex. We note, however, that there are still potential systematics that could affect the overall mass calibration at the level of a factor of a few.

scholarly journals Probing black hole accretion tracks, scaling relations, and radiative efficiencies from stacked X-ray active galactic nuclei

2019 ◽  
Vol 493 (1) ◽  
pp. 1500-1511 ◽  
Author(s):  
Francesco Shankar ◽  
David H Weinberg ◽  
Christopher Marsden ◽  
Philip J Grylls ◽  
Mariangela Bernardi ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Selection Bias ◽  
Stellar Mass ◽  
Supermassive Black Holes ◽  
Independent Evidence ◽  
X Ray ◽  
Black Hole Accretion ◽  
Black Hole Masses ◽  
Hole Accretion

ABSTRACT The masses of supermassive black holes at the centres of local galaxies appear to be tightly correlated with the mass and velocity dispersions of their galactic hosts. However, the local Mbh–Mstar relation inferred from dynamically measured inactive black holes is up to an order-of-magnitude higher than some estimates from active black holes, and recent work suggests that this discrepancy arises from selection bias on the sample of dynamical black hole mass measurements. In this work, we combine X-ray measurements of the mean black hole accretion luminosity as a function of stellar mass and redshift with empirical models of galaxy stellar mass growth, integrating over time to predict the evolving Mbh–Mstar relation. The implied relation is nearly independent of redshift, indicating that stellar and black hole masses grow, on average, at similar rates. Matching the de-biased local Mbh–Mstar relation requires a mean radiative efficiency ε ≳ 0.15, in line with theoretical expectations for accretion on to spinning black holes. However, matching the ‘raw’ observed relation for inactive black holes requires ε ∼ 0.02, far below theoretical expectations. This result provides independent evidence for selection bias in dynamically estimated black hole masses, a conclusion that is robust to uncertainties in bolometric corrections, obscured active black hole fractions, and kinetic accretion efficiency. For our fiducial assumptions, they favour moderate-to-rapid spins of typical supermassive black holes, to achieve ε ∼ 0.12–0.20. Our approach has similarities to the classic Soltan analysis, but by using galaxy-based data instead of integrated quantities we are able to focus on regimes where observational uncertainties are minimized.

scholarly journals Quasar Mass Functions Across Cosmic Time

2009 ◽  
Vol 5 (S267) ◽  
pp. 239-247
Author(s):  
Marianne Vestergaard
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Cosmic Time ◽  
Wide Range ◽  
Mass Functions ◽  
Black Hole Masses ◽  
Cosmic History

AbstractI present mass functions of actively accreting black holes detected in different quasar surveys which in concert cover a wide range of cosmic history. I briefly address what we learn from these mass functions. I summarize the motivation for such a study and the methods by which we determine black hole masses.

scholarly journals Explosion of very massive stars and the origin of intermediate mass black holes

2006 ◽  
Vol 2 (S238) ◽  
pp. 241-246
Author(s):  
Sachiko Tsuruta ◽  
Takuya Ohkubo ◽  
Hideyuki Umeda ◽  
Keiichi Maeda ◽  
Ken'ichi Nomoto ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Massive Stars ◽  
Core Collapse ◽  
Clusters Of Galaxies ◽  
Intermediate Mass ◽  
Black Hole Masses ◽  
Better Than ◽  
Intermediate Mass Black Holes ◽  
Population Iii

AbstractWe calculate evolution, collapse, explosion, and nucleosynthesis of Population III very massive stars with 500 M⊙ and 1000 M⊙. It was found that both 500 M⊙ and 1000 M⊙ models enter the region of pair-instability but continue to undergo core collapse to black holes. For moderately aspherical explosions, the patterns of nucleosynthesis match the observational data of intergalactic and intercluster medium and hot gases in M82, better than models involving hypernovae and pair instability supernovae.Our results suggest that explosions of Population III core-collapse very massive stars contribute significantly to the chemical evolution of gases in clusters of galaxies. The final black hole masses are about 500 M⊙ for our most massive 1000 M⊙ models. This result may support the view that Population III very massive stars are responsible for the origin of intermediate mass black holes which were recently reported to be discovered.

scholarly journals Black Hole Demographics: Statistical Characteristics of Accreting Black Holes

2009 ◽  
Vol 5 (S267) ◽  
pp. 213-222
Author(s):  
Hagai Netzer
Keyword(s):  
Growth Rate ◽  
Black Holes ◽  
Black Hole ◽  
High Redshift ◽  
Parallel Evolution ◽  
Statistical Characteristics ◽  
Small Samples ◽  
Host Galaxy ◽  
Data Sets ◽  
Accretion Rates

This review summarizes the important properties of active black holes (BHs) up to z ~ 2; their mass, accretion rate, and growth rate. At higher redshifts, such information is only available for small samples that do not represent the entire population of active galactic nuclei (AGNs). Black hole spin is still unknown; it is speculated to change with redshift, but with little experimental evidence. The available data sets also enable a direct comparison of BH accretion rates and host galaxy star-formation rates (SFRs). The ratio of the BH growth rate g(BH) and the bulge growth rate g(bulge), suggests that the two are proportional to each other. The local value of g(bulge)/g(BH) in low-luminosity AGNs is of order 100 and the corresponding ratio in high-luminosity, high-redshift AGNs is of order 10. This has important implications regarding the parallel evolution of active BHs and their hosts.

Supermassive Black Holes in Active Galactic Nuclei. I. The Consistency of Black Hole Masses in Quiescent and Active Galaxies

2001 ◽  
Vol 555 (2) ◽  
pp. L79-L82 ◽  
Author(s):  
Laura Ferrarese ◽  
Richard W. Pogge ◽  
Bradley M. Peterson ◽  
David Merritt ◽  
Amri Wandel ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Active Galaxies ◽  
Black Hole Masses

scholarly journals AGN and the Demographics of Supermassive Black Holes

2002 ◽  
Vol 184 ◽  
pp. 335-342
Author(s):  
Richard F. Green
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Large Scale ◽  
Velocity Dispersion ◽  
Cosmic Time ◽  
Volume Density ◽  
Supermassive Black Holes ◽  
High Angular Resolution ◽  
Bulge Formation ◽  
Black Hole Masses

AbstractHigh angular resolution observations from WFPC and STIS now allow well-constrained dynamical measurement of the masses of supermassive black holes (SMBH) in nearby galaxies. An initial statistical analysis by Magorrian et al. showed that 97% of bulges host SMBH. Black hole mass is correlated moderately with bulge luminosity and strongly with the velocity dispersion of the whole bulge, suggesting that black hole formation may be an intrinsic aspect of bulge formation. Black hole masses for AGN determined from reverberation mapping fall on the same relationship with bulge velocity dispersion as those determined from stellar dynamical measurements. The prospect is therefore that the large-scale distribution of black hole masses in distant quasars may be determined through relatively straightforward measurement. Integral constraints show consistency between the total AGN luminosity density and the total volume density in SMBH contained in galaxy bulges. The strong peak of the high-luminosity quasar luminosity function at early cosmic time is consistent with the association of the build-up of SMBH through accretion and bulge formation. Alternate scenarios requiring substantial build-up of the most massive black holes at later cosmic times are more difficult to reconcile with the evolution of the LF.

scholarly journals Accurate AGN Black Hole Masses and the Scatter in the MBH–Lbulge Relationship

2009 ◽  
Vol 5 (S267) ◽  
pp. 203-203 ◽  
Author(s):  
C. Martin Gaskell
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Velocity Dispersion ◽  
High Luminosity ◽  
Lower Mass ◽  
Reverberation Mapping ◽  
The Masses ◽  
Black Hole Masses ◽  
The Continuum

AbstractA new empirical formulae is given for estimating the masses of black holes in AGNs from the Hβ velocity dispersion and the continuum luminosity at 5100 Å. It is calibrated to reverberation-mapping and stellar-dynamical estimates of black hole masses. The resulting mass estimates are as accurate as reverberation-mapping and stellar-dynamical estimates. The new mass estimates show that there is very little scatter in the MBH–Lbulge relationship for high-luminosity galaxies, and that the scatter increases substantially in lower-mass galaxies.

scholarly journals Black holes in active galactic nuclei

2009 ◽  
Vol 5 (S261) ◽  
pp. 260-268
Author(s):  
M. J. Valtonen ◽  
S. Mikkola ◽  
D. Merritt ◽  
A. Gopakumar ◽  
H. J. Lehto ◽  
...  
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Strong Field ◽  
Equations Of Motion ◽  
Binary Black Holes ◽  
Time Dynamic ◽  
Black Hole Spacetime ◽  
First Time ◽  
Black Hole Masses

AbstractSupermassive black holes are common in centers of galaxies. Among the active galaxies, quasars are the most extreme, and their black hole masses range as high as to 6⋅1010M⊙. Binary black holes are of special interest but so far OJ287 is the only confirmed case with known orbital elements. In OJ287, the binary nature is confirmed by periodic radiation pulses. The period is twelve years with two pulses per period. The last four pulses have been correctly predicted with the accuracy of few weeks, the latest in 2007 with the accuracy of one day. This accuracy is high enough that one may test the higher order terms in the Post Newtonian approximation to General Relativity. The precession rate per period is 39°.1 ± 0°.1, by far the largest rate in any known binary, and the (1.83 ± 0.01)⋅1010M⊙primary is among the dozen biggest black holes known. We will discuss the various Post Newtonian terms and their effect on the orbit solution. The over 100 year data base of optical variations in OJ287 puts limits on these terms and thus tests the ability of Einstein's General Relativity to describe, for the first time, dynamic binary black hole spacetime in the strong field regime. The quadrupole-moment contributions to the equations of motion allows us to constrain the ‘no-hair’ parameter to be 1.0 ± 0.3 which supports the black hole no-hair theorem within the achievable precision.

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