skip to main content

Title: New observational constraints on the growth of the first supermassive black holes

We constrain the total accreted mass density in supermassive black holes at z > 6, inferred via the upper limit derived from the integrated X-ray emission from a sample of photometrically selected galaxy candidates. Studying galaxies obtained from the deepest Hubble Space Telescope images combined with the Chandra 4 Ms observations of the Chandra Deep Field-South, we achieve the most restrictive constraints on total black hole growth in the early universe. We estimate an accreted mass density <1000 M {sub ☉} Mpc{sup –3} at z ∼ 6, significantly lower than the previous predictions from some existing models of early black hole growth and earlier prior observations. These results place interesting constraints on early black hole growth and mass assembly by accretion and imply one or more of the following: (1) only a fraction of the luminous galaxies at this epoch contain active black holes; (2) most black hole growth at early epochs happens in dusty and/or less massive—as yet undetected—host galaxies; (3) there is a significant fraction of low-z interlopers in the galaxy sample; (4) early black hole growth is radiatively inefficient, heavily obscured, and/or due to black hole mergers as opposed to accretion; or (5) the bulk of themore » black hole growth occurs at late times. All of these possibilities have important implications for our understanding of high-redshift seed formation models.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. Universidad de Concepción, Departamento de Astronomía, Casilla 160-C, Concepción (Chile)
  2. Institute for Astronomy, Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 16, CH-8093 Zurich (Switzerland)
  3. Institut d' Astrophysique de Paris, 98bis Blvd., Arago, F-75014 Paris (France)
  4. Yale Center for Astronomy and Astrophysics, P.O. Box 208121, New Haven, CT 06520 (United States)
Publication Date:
OSTI Identifier:
22341922
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 778; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BLACK HOLES; DENSITY; EMISSION; FORECASTING; HOST; LIMITING VALUES; MASS; RED SHIFT; SPACE; TELESCOPES; UNIVERSE; X RADIATION; X-RAY GALAXIES