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X-rays are a critical wavelength for understanding supermassive black holes (SMBHs). X-rays probe the inner accretion flow, closest to the event horizon, where gas inspirals, releasing energy and driving black hole growth. This region also…

High Energy Astrophysical Phenomena · Physics 2025-04-01 Erin Kara , Javier García

Context. Motivated by the recent achievements of a full general relativistic method in determining black hole (BH) parameters, we continue to estimate the mass-to-distance ratio of the supermassive BHs hosted at the core of the active…

Astrophysics of Galaxies · Physics 2024-09-18 A. González-Juárez , M. Momennia , A. Villalobos-Ramírez , A. Herrera-Aguilar

Type II AGNs with polarimetric broad emission line provided strong evidence for the orientation-based unified model for AGNs. We want to investigate whether the polarimetric broad emission line in type II AGNs can be used to calculate their…

Astrophysics · Physics 2009-11-13 Shi-Yan Zhang , Wei-Hao Bian , Ke-Liang Huang

The accretion efficiency for individual black holes is very difficult to determine accurately. There are many factors that can influence each step of the calculation, such as the dust and host galaxy contribution to the observed luminosity,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 S. I. Raimundo , A. C. Fabian , R. V. Vasudevan , P. Gandhi , Jianfeng Wu

It is well known that reverberation mapping of active galactic nuclei (AGN) reveals a relationship between AGN luminosity and the size of the broad-line region, and that use of this relationship, combined with the Doppler width of the broad…

The origin of the tight scaling relation between the mass of supermassive black holes (SMBHs; $M_{\rm BH}$) and their host-galaxy properties remains unclear. Active galactic nuclei (AGNs) probe phases of ongoing SMBH growth and offer the…

The applicability and apparent uncertainties of the techniques currently available for measuring or estimating black-hole masses in AGNs are briefly summarized.

Astrophysics · Physics 2007-05-23 M. Vestergaard

Black hole masses in active galactic nuclei (AGN) are difficult to measure using conventional dynamical methods, but can be determined using the technique of reverberation mapping. However, it is important to verify that the results of…

Astrophysics · Physics 2009-11-10 Charles H. Nelson , Richard F. Green , Gary Bower , Karl Gebhardt , Donna Weistrop

The mass estimator used to calculate black hole (BH) masses in broad-line active galactic nuclei (AGNs) relies on a virial coefficient (the "$f$ factor") that is determined by comparing reverberation-mapped (RM) AGNs with measured bulge…

Astrophysics of Galaxies · Physics 2015-06-22 Luis C. Ho , Minjin Kim

The colossal power output of active galactic nuclei (AGN) is believed to be fueled by the accretion of matter onto a supermassive black hole. This central accreting region of AGN has hitherto been spatially unresolved and its structure…

Astrophysics · Physics 2009-10-30 B. McKernan , T. Yaqoob

We investigate the relation of black hole mass versus host stellar mass and that of mass accretion rate versus star formation rate (SFR) in moderately luminous ($\log L_{\rm bol} \sim 44.5-46.5\ {\rm erg\ s^{-1}}$), X-ray selected…

Astrophysics of Galaxies · Physics 2021-03-24 Kenta Setoguchi , Yoshihiro Ueda , Yoshiki Toba , Masayuki Akiyama

Understanding the relationship between galaxies hosting active galactic nuclei (AGN) and the dark matter halos in which they reside is key to constraining how black-hole fueling is triggered and regulated. Previous efforts have relied on…

Astrophysics of Galaxies · Physics 2015-06-23 A. Leauthaud , A. J. Benson , F. Civano , A. L. Coil , K. Bundy , R. Massey , M. Schramm , A. Schulze , P. Capak , M. Elvis , A. Kulier , J. Rhodes

Supermassive Black Holes (BHs) are known to efficiently grow through gas accretion, but even sustained and intense mass build-up through this mechanism struggles to explain the assembly of the most massive BHs observed in the local…

The clustering of active galactic nuclei (AGN) sheds light on their typical large (Mpc-scale) environments, which can constrain the growth and evolution of supermassive black holes. Here we measure the clustering of luminous X-ray-selected…

Astrophysics of Galaxies · Physics 2020-03-11 M. C. Powell , C. M. Urry , N. Cappelluti , J. T. Johnson , S. M. LaMassa , T. T. Ananna , K. E. Kollmann

We have embarked in an HST program to determine the masses of black holes in spiral galaxies directly by measuring the line emission arising from an extended accretion disk. For each of the galaxies in our sample we have measured the…

Astrophysics · Physics 2009-11-10 Duccio Macchetto

A long-standing question is whether active galactic nuclei (AGN) vary like Galactic black hole systems when appropriately scaled up by mass (refs 1-3). If so, we can then determine how AGN should behave on cosmological timescales by…

Astrophysics · Physics 2011-05-05 I M McHardy , E Koerding , C Knigge , P Uttley , R P Fender

We present a multi-wavelength analysis of three candidate active galactic nuclei (AGNs) in low-mass galaxies in the Bo\"otes field with the aim of improving constraints on the occupation fraction of low-mass black holes (BHs). Galaxies with…

Astrophysics of Galaxies · Physics 2025-02-20 Rujuta A. Purohit , Ryan C. Hickox , Grayson C. Petter

This letter presents, for the first time, direct constraints on the black-hole-to-halo-mass relation using weak gravitational lensing measurements. We construct type I and type II Active Galactic Nuclei (AGNs) samples from the Sloan Digital…

Recent Chandra and XMM-Newton surveys have uncovered a large fraction of the obscured AGN responsible of the hard X-ray background. One of the most intriguing results of extensive programs of follow-up observations concerns the optical and…

Astrophysics · Physics 2009-11-10 Andrea Comastri , Fabrizio Fiore

Spectroscopic reverberation mapping (RM) is a direct approach widely used to estimate the mass of black holes (BHs) in active galactic nuclei (AGNs). However, it is very time consuming and difficult to apply to a large AGN sample. The…

Astrophysics of Galaxies · Physics 2023-05-30 Shu Wang , Hengxiao Guo , Jong-Hak Woo
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