Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 0708.0942

Evolution of supermassive black holes

Andreas Mueller·Guenther Hasinger
View original source ↗Read source document ↗Export metadata ↓

Abstract

The cosmological evolution of supermassive black holes (SMBHs) seems to be intimately linked to their host galaxies. Active galactic nuclei (AGN) can be probed by deep X-ray surveys. We review results from large X-ray selected samples including first results from the XMM-Newton COSMOS survey. A new picture arises from the fact that high-luminosity AGN grow earlier than low-luminosity AGN. In particular, the space density of low-luminosity AGN exhibits a significant decline for redshifts above z=1. This 'anti--hierarchical' growth scenario of SMBHs can be explained by two modes of accretion with different efficiency. The population of Compton-thick sources plays a key role in our understanding of the BH growth history. Their space density and redshift distribution is relevant to estimate the SMBH mass function. A comparison with the relic SMBH mass distribution in the local Universe constrains the average radiative efficiency and Eddington ratio of the accretion. We discuss a new synthesis model of Compton-thin and Compton-thick sources that is in concordance with deep X-ray observations and in particular predicts the right level of contribution of the Compton-thick source population observed in the Chandra Deep Field South observations as well as the first INTEGRAL and Swift catalogues of AGN. Currently, one of the most important problems is the evolution of obscuration with redshift.

Explore related subjects

astro-ph

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Andreas Mueller, Guenther Hasinger. 2007-08-07. Evolution of supermassive black holes. https://arxiv.org/abs/0708.0942

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

The mildly nonlinear imprint of structure on the CMB: the $O(\ell)$ couplings are lensing and aberration

The exact 1+3 covariant multipole hierarchy for the CMB brightness contains kinematic couplings between the shear, acceleration and vorticity of the observers and the temperature multipoles, whose coefficients grow linearly in $\ell$. They are products of first-order quantities, so linearization about FLRW removes them. Here they are kept as sources in a weakly nonlinear extension of the almost-FLRW temperature anisotropies, and evaluated in the aligned-wavevector, weak-coupling limit. In the Newtonian frame the acceleration terms cancel at leading order in $1/\ell$. In the total (CDM) frame the shear terms cancel in the same way, to a residual of about $3/\ell$ of either term. Earlier versions of this paper reported that the total-frame terms do not cancel, and inferred a mildly nonlinear Rees-Sciama imprint near $\ell \sim 100 - 300$. That result came from a sign misprint in the $\ell-2$ shear coupling and is withdrawn; see the Note added. The $O(\ell)$ couplings are the multipole form of gravitational lensing and observer aberration, both already in the standard treatment. The explicit kinematic couplings written here are only part of the full second-order propagation source; the perturbed free-streaming contribution is linearized away in this paper.

astro-ph↗
arXiv2026

Cosmic Conundrums with Quantum Corrections

Darh energy was discovered over 25 years ago and we do not have an explanation of it. Dark matter comprises 95% of matter in the universe and we still don't know what it is. The Webb telescope has been finding fully formed galaxies with massive black holes millions of times the mass of the sun in the early universe and we don't have any explanation. A quantum density limitation will be used to solve these and other outstanding problems.

astro-ph↗
arXiv2026

On binary pulsars and the force of gravity

The energy-momentum budget of the astrophysical systems can be studied by the exact local conservation equation derived by Landau and Lifshitz. We show that a similar equation is valid for the Einstein-Cartan gravity. We reanalyze a binary pulsar system using the Landau-Lifshitz conservation equation and show that the orbital period change rate can be completely understood as a curvature backreaction process. Taking into account the detailed theoretical and observational research of relativistic binary pulsar systems, especially the system of Hulse and Taylor, we conclude that general relativity and astrophysical observations rule out the existence of gravitational radiation. We comment upon the LIGO GW events and their alternative explanation, as well as the recent pulsar timing arrays data.

astro-ph↗