Related papers: Cosmological Evolution of Quasars
We consider a class of models for the redshift evolution (between $0\lsim z \lsim 4$) of the observed optical and X-ray quasar luminosity functions (LFs), with the following assumptions: (i) the mass-function of dark matter halos follows…
Quasars (QSOs) emit an enormous amount of light as a result of the accretion of gas onto supermassive black holes (SMBHs). Thanks to their luminosity, the most distant known QSOs allow us to trace the growth of SMBHs deep into the epoch of…
We present a flexible framework for constructing physical models of quasar evolution that can incorporate a variety of observational constraints, such as multi-wavelength luminosity functions, estimated masses and accretion rates of active…
We discuss a simple model for the growth of supermassive black holes (BHs) at the center of spheroidal stellar systems. In particular, we assess the hypotheses that (1) star formation in spheroids and BH fueling are proportional to one…
We derive quantitative predictions of the optical and X-ray luminosity functions (LF) for QSs in the redshift range $z<3$. Based on BH paradigm, we investigate how the accretion is controlled by the surrounding structures, as these grow…
Growth of massive black holes (MBHs) in galactic centers comes mainly from gas accretion during their QSO/AGN phases. In this paper we apply an extended Soltan argument, connecting the local MBH mass function with the time-integral of the…
Quasars are widely believed to be powered by accretion onto supermassive black holes and there is now considerable evidence for a link between mergers, quasars and the formation of spheroids. Cattaneo, Haehnelt & Rees (1999) have…
Based on the physical model of a supermassive black hole (SMBH) growth via gas accretion in a circumnuclear disk (CND) proposed by Kawakatu & Wada (2008), we describe the formation of high-$z$ ($z > 6$) quasars (QSOs) whose BH masses are…
The evolution of luminous QSOs is linked to the evolution of massive galaxies. We know this because the relic black-holes found locally have masses dependent on the properties of the host galaxy's bulge. An important way to explore this…
We demonstrate that the luminosity function of the recently detected population of star-forming galaxies and the QSO luminosity function at z=3 can be matched with the mass function of dark matter haloes predicted by hierarchical…
It has long been believed that accretion onto supermassive black holes powers quasars, but there has been relatively few observational constraints on the spins of the black holes. We address this problem by estimating the average radiative…
In this Letter, we present a model connecting the cosmic star formation rate (CSFR) to the growth of supermassive black holes. Considering that the evolution of the massive black hole is dominated by accretion (Soltan's argument) and that…
Episodic activity of quasars is driving growth of supermassive black holes (SMBHs) via accretion of baryon gas. In this Letter, we develop a simple method to analyse the duty cycle of quasars up to redshift $z\sim 6$ universe from…
We have derived the quasar luminosity function assuming that the quasar activity is driven by a thermal-viscous unstable accretion disk around a supermassive black hole. The instabilities produce large amplitude, long-term variability of a…
The early evolution of the quasar luminosity function (QLF) and black hole mass function (BHMF) encodes key information on the physics determining the radiative and accretion processes of supermassive black holes (BHs) in high-$z$ quasars.…
Quasars, powered by accretion onto supermassive black holes (SMBHs), exhibit significant variability, offering insights into the physics of accretion and the properties of the central engines. In this study, we analyze photometric…
We investigate how accretion episodes onto massive black holes power quasars and AGN while they accumulate mass into the holes. We compute both the trend and the stochastic component to the trigger of the accretion events, as provided by…
The spin is an important but poorly constrained parameter for describing supermassive black holes (SMBHs). Using the continuity equation of SMBH number density, we explicitly obtain the mass-dependent cosmological evolution of the radiative…
Quasars are powered by accretion onto supermassive black holes, but the problem of the duty cycle related to the episodic activity of the black holes remains open as one of the major questions of cosmological evolution of quasars. In this…
We explore the connection between black hole growth at the center of obscured quasars selected from the XMM-COSMOS survey and the physical properties of their host galaxies. We study a bolometric regime (<Lbol > 8 x 10^45 erg/s) where…