Formation of z~6 Quasars from Hierarchical Galaxy Mergers

By Yue-xing Li, L. Hernquist, Brant Robertson, Thomas J. Cox, P. Hopkins, Volker Springel, Liang Gao, T. Di Matteo, A. Zentner, Adrian Jenkins and 1 more. 2006

261 citations recorded by the source corpus.

The discovery of luminous quasars at redshift z ~ 6 indicates the presence of supermassive black holes (SMBHs) of mass ~109 M☉ when the universe was less than 1 billion years old. This finding presents several challenges for theoretical models because whether such massive objects can form so early in the ΛCDM cosmology, the leading theory for cosmic structure formation, is an open question. Furthermore, whether the formation process requires exotic physics such as super-Eddington accretion remains undecided. Here we present the first multiscale simulations that, together with a self-regulated model for the SMBH growth, produce a luminous quasar at z ~ 6.5 in the ΛCDM paradigm. We follow the hierarchical assembly history of the most massive halo in a ~3 Gpc3 volume and find that this halo of ~8 × 1012 M☉ 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 vigorous star formation (up to 104 M☉ yr-1) preceding the major quasar phase such that the stellar mass of the quasar host reaches 1012 M☉ at z ~ 6.5, consistent with observations of significant metal enrichment in SDSS J1148+5251. The merger remnant thus obeys a similar MBH-Mbulge scaling relation observed locally as a consequence of coeval growth and evolution of the SMBH and its host galaxy. Our results provide a viable formation mechanism for z ~ 6 quasars in the standard ΛCDM cosmology and demonstrate a common, merger-driven origin for the rarest quasars and the fundamental MBH-Mbulge correlation in a hierarchical universe.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/9d478f2e63f24bdc7e9b06e34b79e9d23c8a5c8f

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Citations in the corpus

Stellar sources of dust in the high-redshift Universe (2009, methodology): “Following Li et al. (2007), we assume that the QSO is hosted by a dark matter halo of mass 1013M⊙ and that the initial mass in baryons is equal to the universal value,Ωb/Ωm, i.e.∼ 1.3× 1012M⊙.”
Cool Gas in High-Redshift Galaxies (2013, background): “Large scale cosmological simulations show that massive galaxies and SMBH can form at z ∼ 6 via gas rich mergers, driving extreme starbursts, and rapid accretion onto the black holes, with subsequent black hole mergers (Li et al. 2007).”
A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies. I. Galaxy Mergers and Quasar Activity (2007, background): “…consequences of mergers at the highest redshifts may be—if merger rates are sufficiently high, there may be a large number of multiple mergers (as in Li et al. 2007), or systems may effectively be so gas-rich that merging preserves disks and operates as a means of ‘‘clumpy accretion’’ (e.g.,…”
A physical model for z∼ 2 dust-obscured galaxies (2009, unknown): “Merger remnants, in our simulations, lie on the MBH–Mbulge relation owing to the termination of the starburst event by AGN feedback, and self-regulation of black hole growth (Di Matteo et al. 2005; Robertson et al. 2006; Hopkins et al. 2007c; Li et al. 2007; Younger et al. 2008b).”
THE CANADA–FRANCE HIGH-z QUASAR SURVEY: NINE NEW QUASARS AND THE LUMINOSITY FUNCTION AT REDSHIFT 6 (2009, methodology): “Theoretical models based on Eddington-limited accretion of the z = 6 quasar population traced back to earlier epochs predict that the black hole accretion rate density is somewhere between 10 and 100 times lower at z = 9 than z = 6 (Li et al. 2007; Sijacki et al. 2009).”
ACCRETION ONTO THE FIRST STELLAR-MASS BLACK HOLES (2007, methodology): “This technique was recently used by Li et al. (2007) and Pelupessy, Di Matteo, & Ciardi (2007) to study the growth of Pop III remnant black holes.”
The realm of the galaxy protoclusters (2016, background): “Their very low space density of about 1 per Gpc3 implies a (maximum) host halo mass of ∼ 1013 M (e.g., Fan et al., 2001; Springel et al., 2005; Li et al., 2007).”
A JWST/NIRSpec First Census of Broad-line AGNs at z = 4–7: Detection of 10 Faint AGNs with M BH ∼ 106–108 M ⊙ and Their Host Galaxy Properties (2023, background): “Although the underlying physical mechanisms are still under debate, theoretical models suggest that feedback of active galactic nuclei (AGNs) connected to galaxy’s merger histories play an important role (e.g., Granato et al. 2004; Di Matteo et al. 2005; Hopkins et al. 2006; Li et al. 2007).”
Primordial star formation under the influence of far ultraviolet radiation: 1540 cosmological haloes and the stellar mass distribution (2015, background): “They do not contribute to the early chemical evolution but leave remnant black holes that might have seeded the formation of supermassive black holes (Li et al. 2007).”
Evidence for Quasar Activity Triggered by Galaxy Mergers in HST Observations of Dust-reddened Quasars (2007, background): “Five of our galaxies show very dramatic, likely multiple merger morphologies, reminiscent of the simulations of high-z quasar hosts by Li et al. (2007).”
Fluctuations in the high-redshift Lyman–Werner background: close halo pairs as the origin of supermassive black holes (2008, background): “…and mergers, starting from stellar–mass seed BHs left behind by the first generation of stars (e.g. Haiman & Loeb 2001; Haiman 2004; Yoo & Miralda-Escudé 2004; Bromley, Somerville & Fabian 2004; Shapiro 2005; Volonteri & Rees 2006; Li et al. 2007; Johnson & Bromm 2007; Tanaka & Haiman 2008).”
The first galaxies : assembly, cooling and the onset of turbulence (2008, background): “The most sophisticated simulations of supermassive black hole (SMBH) growth to date have been conducted by Li et al. (2007), but their resolution was insufficient to trace the origin of SMBHs below ≃ 105 M⊙.”
The Destruction of Cosmological Minihalos by Primordial Supernovae (2008, background): “…this mechanism may provide the means whereby black holes of several thousand solar masses could form in pregalactic structures at z 20, which numerical studies suggest could be the origin of the supermassive black holes occupying the centers of most massive galaxies today (Li et al. 2007).”
CANDELS: THE COSMIC ASSEMBLY NEAR-INFRARED DEEP EXTRAGALACTIC LEGACY SURVEY (2011, unknown): “For example, if early black hole growth is mainly merger-driven (Li et al. 2007), one would expect both coeval star formation and a substantial stellar population associated with the AGN.”
STAR FORMATION AND GAS KINEMATICS OF QUASAR HOST GALAXIES AT z ∼ 6: NEW INSIGHTS FROM ALMA (2013, background): “15 Hubble Fellow. highest redshift suggests fast black hole accretion and significant SMBH-galaxy evolution within 1 Gyr after the big bang (Li et al. 2007; Narayanan et al. 2008; Di Matteo et al. 2012).”
A SURVEY OF z ∼ 6 QUASARS IN THE SLOAN DIGITAL SKY SURVEY DEEP STRIPE. I. A FLUX-LIMITED SAMPLE AT zAB < 21 (2007, background): “…at z ∼ 6 puts strong constraints on models of BH growth (e.g. Wyithe & Loeb 2003; Hopkins et al. 2005; Volonteri & Rees 2006; Wyithe & Padmanabhan 2006; Li et al. 2007), and helps determine whether standard models of radiatively efficient Eddington accretion from stellar seeds are still allowed,…”
IMAGING THE MOLECULAR GAS IN A SUBMILLIMETER GALAXY AT z = 4.05: COLD MODE ACCRETION OR A MAJOR MERGER? (2010, background): “Major gas rich mergers have been invoked to explain the compact, maximal starbursts seen in some high redshift quasar host galaxies (Li et al. 2007; Walter et al. 2009; Riechers et al. 2009).”
A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies. II. Formation of Red Ellipticals (2007, background): “…the dynamic range to simultaneously resolve the relevant galactic structure and feedback processes and cosmologically rare, massive populations are not yet feasible; however, the effects of these processes in representative systems can be studied in detailed zoom-in simulations (Li et al. 2007).”