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We constrain the number density and evolution of Compton-thick Active Galactic Nuclei (AGN). In the local Universe we use the wide area surveys from the Swift and INTEGRAL satellites, while for high redshifts we explore candidate selections…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-18 E. Treister , C. Megan Urry , Shanil Virani

(Abridged) Using an empirical relation between the broad line region size and optical continuum luminosity, we estimated the black hole mass and accretion rate for 135 AGNs with double-peaked broad emission lines in two samples. With black…

Astrophysics · Physics 2009-11-10 Xue-Bing Wu , F. K. Liu

We investigate the accretion-driven growth of supermassive black holes in the low-redshift Universe using 23,000 ``Type 2'' AGN and the complete sample of 123,000 galaxies in the SDSS from which they were drawn. We use the stellar velocity…

We use 317,000 emission-line galaxies from the Sloan Digital Sky Survey to investigate line-ratio selection of active galactic nuclei (AGNs). In particular, we demonstrate that "star formation dilution" by HII regions causes a significant…

Previous studies of the active galactic nuclei (AGN) contribution to the cosmic X-ray background (CXB) consider only observable parameters such as luminosity and absorbing column. Here, for the first time, we extend the study of the CXB to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 A. R. Draper , D. R. Ballantyne

We present new Chandra X-ray observations of seven low-mass black holes (~1e6 Msun) accreting at low Eddington ratios between -2.0<log L/Ledd<-1.5. We compare the X-ray properties of these seven low-mass active galactic nuclei (AGN) to a…

High Energy Astrophysical Phenomena · Physics 2025-10-14 Richard M. Plotkin , Elena Gallo , Francesco Haardt , Brendan P. Miller , Abigail J. Wood , Amy E. Reines , Jianfeng Wu , Jenny E. Greene

Aims: We investigate the cosmological growth of dark halos and follow the consequences of coeval growth for the accretion history of associated supermassive black holes. Methods: The Press-Schechter approximation is used to obtain an…

Astrophysics · Physics 2009-11-11 L. Miller , W. J. Percival , S. M. Croom , A. Babic

We present the identification and analysis of an unbiased sample of AGN that lie within the local galaxy population. Using the MPA-JHU catalogue (based on SDSS DR8) and 3XMM DR7 we define a parent sample of 25,949 local galaxies ($z \leq…

Astrophysics of Galaxies · Physics 2021-12-15 Keir L. Birchall , M. G. Watson , J. Aird , R. L. C. Starling

We study the distribution of Eddington luminosity ratios, L_bol/L_edd, of active galactic nuclei (AGNs) discovered in the AGN and Galaxy Evolution Survey (AGES). We combine H-beta, MgII, and CIV line widths with continuum luminosities to…

We present a comprehensive spectroscopic and variability-based characterisation of a sample of low-luminosity active galactic nuclei (AGNs) hosting low mass black holes, identified by $H\beta$ full width at half maximum (FWHM) $< 2200$ km…

Astrophysics of Galaxies · Physics 2025-12-09 Himanshu Sharma , Vivek Kumar Jha , Hum Chand , Swayamtrupta Panda

We use a phenomenological model to show that black hole growth in the local Universe (z < 0.1) can be described by two separate, mass independent Eddington ratio distribution functions (ERDFs). We assume that black holes can be divided into…

Astrophysics of Galaxies · Physics 2017-08-30 Anna K. Weigel , Kevin Schawinski , Neven Caplar , O. Ivy Wong , Ezequiel Treister , Benny Trakhtenbrot

Eddington ratio is a paramount parameter governing the accretion history and life cycles of Active Galactic Nuclei (AGNs). This short review presents a multi-faceted view of the importance of the Eddington ratio spanning varied AGN studies.…

Active galactic nuclei (AGN) have been observed in dwarf galaxies, yet the impact of black hole feedback in these low-mass systems remains unclear. To uncover the potential effects of AGN in the low-mass galaxy regime, we study the…

Accretion disks of active galactic nuclei (AGN) have been proposed as promising sites for producing both (stellar-mass) compact object mergers and extreme mass ratio inspirals. Along with the disk-assisted migration/evolution process,…

High Energy Astrophysical Phenomena · Physics 2022-01-05 Zhen Pan , Huan Yang

The majority of nearby radio-loud AGN are found in massive, old elliptical galaxies with weak emission lines. At high redshifts,however, most known radio AGN have strong emission lines. In this paper, we examine a subset of radio AGN with…

Astrophysics · Physics 2009-11-13 Guinevere Kauffmann , Timothy M. Heckman , Philip N. Best

The large-scale environments of active galactic nuclei (AGN) reveal important information on the growth and evolution of supermassive black holes (SMBHs). Previous AGN clustering measurements using 2-point correlation functions have hinted…

Astrophysics of Galaxies · Physics 2025-09-03 A. Mhatre , M. C. Powell , S. Yuan , S. W. Allen , T. Caglar , M. Koss , I. del Moral-Castro , K. Oh , A. Peca , C. Ricci , F. Ricci , A. Rojas , M. Signorini

We estimated black hole masses and Eddington ratios for a well defined sample of local (z<0.3) broad line AGN from the Hamburg/ESO Survey (HES), based on the Hbeta line and standard recipes assuming virial equilibrium for the broad line…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Andreas Schulze , Lutz Wisotzki

We map the co-eval growth of galaxies and their central supermassive black holes in detail by measuring the incidence of Active Galactic Nuclei (AGN) in galaxies as a function of star formation rate (SFR) and redshift (to z~4). We combine…

Astrophysics of Galaxies · Physics 2019-02-20 James Aird , Alison L. Coil , Antonis Georgakakis

A recent revision of black hole scaling relations (Kormendy & Ho 2013), indicates that the local mass density in black holes should be increased by up to a factor of five with respect to previously determined values. The local black hole…

Astrophysics of Galaxies · Physics 2015-02-11 A. Comastri , R. Gilli , A. Marconi , G. Risaliti , M. Salvati

The standard alpha-disc model predicts an anti-correlation between the density of the inner accretion disc and the black hole mass times square of the accretion rate, as seen in higher mass ($M_{\rm BH}>10^{6} M_{\odot}$) active galactic…