scholarly journals The cosmological history of accretion onto dark halos and supermassive black holes

2006 ◽  
Vol 459 (1) ◽  
pp. 43-54 ◽  
Author(s):  
L. Miller ◽  
W. J. Percival ◽  
S. M. Croom ◽  
A. Babić
2012 ◽  
Vol 8 (S290) ◽  
pp. 259-260 ◽  
Author(s):  
Yan-Rong Li ◽  
Jian-Min Wang ◽  
Luis C. Ho

AbstractWe derive the mass function of supermassive black holes (SMBHs) over the redshift range 0 > z ≲ 2, using the latest deep luminosity and mass functions of field galaxies. Applying this mass function, combined with the bolometric luminosity function of active galactic nuclei (AGNs), into the the continuity equation of SMBH number density, we explicitly obtain the mass-dependent cosmological evolution of the radiative efficiency for accretion. We suggest that the accretion history of SMBHs and their spins evolve in two distinct regimes: an early phase of prolonged accretion, plausibly driven by major mergers, during which the black hole spins up, then switching to a period of random, episodic accretion, governed by minor mergers and internal secular processes, during which the hole spins down. The transition epoch depends on mass, mirroring other evidence for “cosmic downsizing” in the AGN population.


2006 ◽  
Vol 2 (S238) ◽  
pp. 287-290 ◽  
Author(s):  
Chris D. Impey ◽  
Jon R. Trump ◽  
Pat J. McCarthy ◽  
Martin Elvis ◽  
John P. Huchra ◽  
...  

AbstractThe Cosmic Evolution Survey (COSMOS) is an HST/ACS imaging survey of 2 square degrees centered on RA = 10:00:28.6, Dec = + 02:12:21 (J2000). While the primary goal of the survey is to study evolution of galaxy morphology and large scale structure, an extensive multi-wavelength data set allows for a sensitive survey of AGN. Spectroscopy of optical counterparts to faint X-ray and radio sources is being carried out with the Magallen (Baade) Telescope and the ESO VLT. By achieving ∼80 redshift completeness down to I AB = 3, the eventual yield of AGN will be ∼1100 over the whole field.Early results on supermassive black holes are described. The goals of the survey include a bolometric census of AGN down to moderate luminosities, the cosmic evolution and fueling history of the central engines, and a study of AGN environments on scales ranging from the host galaxy to clusters and superclusters.


2017 ◽  
Vol 471 (4) ◽  
pp. 4398-4411 ◽  
Author(s):  
M. Paolillo ◽  
I. Papadakis ◽  
W. N. Brandt ◽  
B. Luo ◽  
Y. Q. Xue ◽  
...  

2006 ◽  
Vol 2 (S238) ◽  
pp. 345-346
Author(s):  
Carlos H. Coimbra-Araújo ◽  
Amâncio C. S. Friaça

AbstractWe show, performing a viable cosmological window, that only the magneto hydrodynamic (MHD) disk model is capable to explain how an intermediate mass black hole (IMBH) (with masses ∼ 103M⊙) grows unto a supermassive black hole (SMBH) (with masses ∼ 107M⊙). We still calculate the supermassive stars sequence of stability. Those stars, with synthetized helium or oxygen cores, collapse to form IMBHs. In our calculation we show that the primordial stars must have rapid rotation if they are in the stable part of the sequence.


2012 ◽  
Vol 2012 ◽  
pp. 1-21 ◽  
Author(s):  
Ezequiel Treister ◽  
C. Megan Urry

Significant progress has been made in the last few years on understanding how supermassive black holes form and grow. In this paper, we begin by reviewing the spectral signatures of active galactic nuclei (AGN) ranging from radio to hard X-ray wavelengths. We then describe the most commonly used methods to find these sources, including optical/UV, radio, infrared, and X-ray emission, and optical emission lines. We then describe the main observational properties of the obscured and unobscured AGN population. Finally, we summarize the cosmic history of black hole accretion, that is, when in the history of the universe supermassive black holes were getting most of their mass. We finish with a summary of open questions and a description of planned and future observatories that are going to help answer them.


Sign in / Sign up

Export Citation Format

Share Document