Formation of z ~ 6 quasars from hierarchical galaxy mergers

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dc.creatorLi, Yuexing
dc.creatorHernquist, Lars
dc.creatorRobertson, Brant
dc.creatorCox, Thomas J.
dc.creatorHopkins, Philip F.
dc.creatorSpringel, Volker
dc.creatorGao, Liang
dc.creatorDi Matteo, Tiziana
dc.creatorZentner, Andrew R.
dc.creatorJenkins, Adrian
dc.creatorYoshida, Naoki
dc.date2006-08-09
dc.date2007-06-26
dc.date.accessioned2026-07-07T11:42:35Z
dc.date.available2026-07-07T11:42:35Z
dc.descriptionThe discovery of luminous quasars at redshift z ~ 6 indicates the presence of supermassive black holes (SMBHs) of mass ~10^9 Msun when the Universe was less than one billion years old. This finding presents several challenges for theoretical models. Here, we present the first multi-scale simulations that, together with a self-regulated model for the SMBH growth, produce a luminous quasar at z ~ 6.5 in the LCDM paradigm. We follow the hierarchical assembly history of the most massive halo in a ~ 3 Gpc^3 volume, and find that this halo of ~ 8x 10^{12} Msun forming at z ~ 6.5 after several major mergers is able to reproduce a number of observed properties of SDSS J1148+5251, the most distant quasar detected at z =6.42 (Fan et al. 2003). Moreover, the SMBHs grow through gas accretion below the Eddington limit in a self-regulated manner owing to feedback. We find that the progenitors experience significant star formation (up to 10^4 Msun/yr) preceding the major quasar phase such that the stellar mass of the quasar host reaches 10^{12} Msun at z ~ 6.5, consistent with observations of significant metal enrichment in SDSS J1148+5251. Our results provide a viable formation mechanism for z ~ 6 quasars in the standard LCDM cosmology, and demonstrate a common, merger-driven origin for the rarest quasars and the fundamental SMBH-host correlation in a hierarchical Universe.(Abridged)
dc.description25 pages, 15 figures, accepted to ApJ. Version with full resolution images is available at http://www.cfa.harvard.edu/~yxli/quasar/quasar.pdf
dc.identifierhttps://arxiv.org/abs/astro-ph/0608190
dc.identifierhttp://arxiv.org/abs/astro-ph/0608190
dc.identifierAstrophys.J.665:187-208,2007
dc.identifierdoi:10.1086/519297
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/200933
dc.subjectAstrophysics
dc.titleFormation of z ~ 6 quasars from hierarchical galaxy mergers
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