A Unified, Merger‐driven Model of the Origin of Starbursts, Quasars, the Cosmic X‐Ray Background, Supermassive Black Holes, and Galaxy Spheroidsстатья из журнала
Аннотация: We develop an evolutionary model for starbursts, quasars, and spheroidal galaxies in which supermassive black holes play a dominant role.In this picture, mergers between gas-rich galaxies drive nuclear inflows of gas, producing intense starbursts and feeding the growth of supermassive black holes.During this phase, the black hole is heavily obscured (a "buried" quasar), but feedback energy from its growth expels the gas, rendering the black hole briefly visible as a bright, optical source (a "visible" quasar), and eventually halting accretion (a "dead" quasar).The self-regulated growth of the black hole accounts for the observed correlation between black hole mass and stellar velocity dispersion in spheroidal galaxies.We show that the quasar lifetime and obscuring column density depend on both the instantaneous and peak luminosities of the quasar, and determine this dependence using a large set of simulations of galaxy mergers varying the host galaxy properties, orbital geometry, and gas physics.We use our fits to the lifetime and column density to deconvolve observed quasar luminosity functions and obtain the evolution of the formation rate of quasars with a certain peak luminosity, ṅ(L peak , z).In our model, quasars spend extended periods of time at luminosities well below their peaks, and so ṅ(L peak , z) has a maximum, falling off at both brighter and fainter luminosities, corresponding to the "break" in the observed quasar luminosity function.We obtain self-consistent fits to hard and soft X-ray and optical quasar luminosity functions for a model in which ṅ(L peak , z) varies with redshift according to pure peak luminosity evolution.From this form for ṅ(L peak , z), and our simulation results for the luminosity dependence of the quasar lifetime and obscuring column, we are able to reproduce many observable quantities, including: the column density distribution of both optical and X-ray selected quasar samples, the luminosity function of broad-line quasars in X-ray samples and the broad-line (Type I, Type II) fraction as a function of luminosity, the mass function of active black holes, the observed distribution of Eddington ratios at both low and high redshift, the present-day mass function of relic, inactive supermassive black holes and total black hole mass density, and the spectrum of the cosmic X-ray background.In each case, our predictions agree well with observations, matching them to higher precision than previous tunable models for quasar lifetimes and obscuration similarly fit to the luminosity function.We provide a library of Monte Carlo realizations of our modeling for comparison with a wide range of observations, using various selection criteria.
Год издания: 2006
Авторы: Philip F. Hopkins, Lars Hernquist, Thomas J. Cox, Tiziana Di Matteo, Brant Robertson, Volker Springel
Издательство: Institute of Physics
Источник: The Astrophysical Journal Supplement Series
Ключевые слова: Galaxies: Formation, Evolution, Phenomena, Astronomy and Astrophysical Research, Gamma-ray bursts and supernovae
Другие ссылки: The Astrophysical Journal Supplement Series (HTML)
Digital Access to Scholarship at Harvard (DASH) (Harvard University) (PDF)
Digital Access to Scholarship at Harvard (DASH) (Harvard University) (HTML)
arXiv (Cornell University) (PDF)
arXiv (Cornell University) (HTML)
DataCite API (HTML)
Digital Access to Scholarship at Harvard (DASH) (Harvard University) (PDF)
Digital Access to Scholarship at Harvard (DASH) (Harvard University) (HTML)
arXiv (Cornell University) (PDF)
arXiv (Cornell University) (HTML)
DataCite API (HTML)
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Том: 163
Выпуск: 1
Страницы: 1–49