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Metal Enrichment of the Intergalactic Medium and Production of Massive Black Holes

Qian, Y.-Z. and Wasserburg, G. J. (2005) Metal Enrichment of the Intergalactic Medium and Production of Massive Black Holes. Astrophysical Journal, 635 (2). pp. 845-852. ISSN 0004-637X. doi:10.1086/497615.

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A model for the chemical evolution of the intergalactic medium (IGM) is presented using theoretical yields of very massive stars (VMSs; M_(VMS) > 100 M_☉) and Type II supernovae (SNe II). It is shown that if [Si/C] is indeed as high as ~0.7 in the IGM, then VMSs (M_(VMS) ≈ 140-260 M_☉) associated with pair-instability supernovae (PI-SNe) in low-mass (~10^5 M_☉) halos at high redshift must produce at least 50% of the Si. The remainder is from later galactic outflows of SN II debris, which also provide most of the C and O. Both sources are required to account for the metal inventory in the IGM. The early VMS production must continue until redshift z ~ 15 so that the efficiency of VMS formation per low-mass halo is significantly below unity. Contributions from the later galactic outflows mainly occur at z ~ 4-6. Using a Salpeter initial mass function, we infer that the number of VMSs (M_(VMS) ≈ 260-2000 M_☉) producing massive black holes (MBHs) with an average mass 〈M_(MBH)〉 ~ 270-550 M_☉ is ≈0.72 times the number of VMSs associated with PI-SNe. The amount of metals (particularly Si) in the IGM that is attributable to PI-SNe is thus closely coupled with the total mass of MBHs produced in epochs prior to galaxy formation. Production of ~50% of the Si in the IGM by PI-SNe corresponds to an early inventory of MBHs that constitutes a fraction ~(4-8) × 10^(-5) of the total baryonic mass in the universe. This is comparable to the global mass budget of the central supermassive black holes (SMBHs) in present-day galaxies. The corresponding occurrence rates in each halo of ~10^5 M_☉ during the epoch of VMS formation at z ≳ 15 are ~0.9 Gyr^(-1) for VMSs associated with PI-SNe and ~0.6 Gyr^(-1) for the concomitant more massive stars producing MBHs. These rates may be of use to studies of H_2 dissociation and reionization and to models of SMBH formation.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Wasserburg, G. J.0000-0002-7957-8029
Additional Information:© 2005 American Astronomical Society. Received 2005 June 17; accepted 2005 September 1. We wish to thank Martin Rees for suggesting that we write this short report separate fromany monographic effort. We also would like to thank the referee, Joop Schaye, for thorough and incisive comments that greatly improved the paper. This work was supported in part by DOE grants DE-FG02-87ER40328 (Y. Z. Q.) and DE-FG03-88ER13851 (G. J. W.), Caltech Division Contribution 9131(1120).
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG02-87ER40328
Department of Energy (DOE)DE-FG03-88ER13851
Subject Keywords: galaxies: formation; intergalactic medium; nuclear reactions, nucleosynthesis, abundances
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Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences9131
Lunatic Asylum Lab1120
Issue or Number:2
Record Number:CaltechAUTHORS:20131211-133315514
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Official Citation: Metal Enrichment of the Intergalactic Medium and Production of Massive Black Holes Y.-Z. Qian and G. J. Wasserburg 2005 ApJ 635 845
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42959
Deposited By: Ruth Sustaita
Deposited On:11 Dec 2013 22:16
Last Modified:10 Nov 2021 16:31

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