ON THE OCCUPATION FRACTION OF SEED BLACK HOLES IN HIGH-REDSHIFT DARK MATTER HALOS

Journal Article · Mon Aug 10 04:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/701/1/360; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21313691

Lippai, Zoltan; Frei, Zsolt ^[1]; Haiman, Zoltan ^[2]

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1. Institute of Physics, Eoetvoes University, Pazmany P. s. 1/A, 1117 Budapest (Hungary)
2. Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States)

It is well known that an initial population of seed black holes (BHs), formed in the nuclei of low-mass galaxies at high redshift, can simultaneously explain, through their subsequent growth by mergers and accretion, both the observed evolution of the quasar luminosity function (LF) and the distribution of remnant supermassive black hole (SMBH) masses measured in local galactic nuclei. Here we consider three very different initial conditions for this scenario: models in which initial seed BHs form in either all, or only a small fraction (f {sub bh} = 0.1 or 0.01) of high-redshift dark matter halos (with M {sub halo} = 5 x 10{sup 9} M {sub sun} at z = 6-10). We show that with a suitable and relatively minor adjustment of two global physical parameters (the radiative efficiency and mass accretion time-scale of quasar episodes), models with f {sub bh} {approx} 0.1 and 1 can accurately reproduce the observed quasar LF at redshifts 0 < z {approx}< 6, as well as the remnant SMBH mass function at z = 0. However, SMBHs remain rare, and the normalization of the high-z quasar LF and the local SMBH mass function are both significantly underpredicted, if f {sub bh} {approx}< 0.01. We also show that the merger history of SMBHs, in the mass range detectable by the future Laser Interferometer Space Antenna (LISA) instrument, generically looks different as f {sub bh} is varied; this should allow LISA to deliver useful constraints on otherwise degenerate models.

• OSTI ID: 21313691
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 701; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
BLACK HOLES
GALACTIC EVOLUTION
GALAXIES
GALAXY NUCLEI
GRAVITATIONAL WAVES
INTERFEROMETERS
LUMINOSITY
MASS
NONLUMINOUS MATTER
QUASARS
RED SHIFT