Cold Flows and the First Quasars

Abstract

Observations of the most distant bright quasars imply that billion solar mass supermassive black holes (SMBHs) have to be assembled within the first 800 million years. Under our standard galaxy formation scenario such fast growth implies large gas densities providing sustained accretion at critical or supercritical rates onto an initial black hole seed. It has been a long standing question whether and how such high black hole accretion rates can be achieved and sustained at the centers of early galaxies. Here we use our new MassiveBlack cosmological hydrodynamic simulation covering a volume (0.75 Gpc) 3 appropriate for studying the rare first quasars to show that steady high density cold gas flows responsible for assembling the first galaxies produce the high gas densities that lead to sustained critical accretion rates and hence rapid growth commensurate with the existence of ∼10 9 M black holes as early as z ∼ 7. We find that under these conditions quasar feedback is not effective at stopping the cold gas from penetrating the central regions and hence cannot quench the accretion until the host galaxy reaches M halo 10 12 M . This cold-flow-driven scenario for the formation of quasars implies that they should be ubiquitous in galaxies in the early universe and that major (proto)galaxy mergers are not a requirement for efficient fuel supply and growth, particularly for the earliest SMBHs.

The origin of the most massive black holes at high-z: BlueTides and the next quasar frontier

“…This also allows us to make predictions for the most massive black holes to be discovered in the near future. Large volume simulations such as MassiveBlack (Di Matteo et al 2012) and associated high-resolutions zooms (Feng et al 2014) already showed that the existence of the z = 6 SDSS quasar population, is consistent with our standard structure formation models. Crucially, the BlueTidessimulation with its increased resolution, allows us to study reliably the formation of massive black holes at even earlier times.…”

“…Here we have focussed our analysis on the massive galaxies and black holes at z 8 (for earlier discussion of z = 6 SDSS quasars, see e.g. Di Matteo et al 2012;Feng et al 2014). In Feng et al (2015 we discussed how the most massive galaxies at these epochs are likely disk dominated.…”

“…In Di Matteo et al (2012) we used the MassiveBlack simulation, a cosmological hydrodynamic simulation covering a volume (0.75 Gpc) 3 appropriate for studying the rare first quasars to show that steady high density cold gas flows responsible for assembling the first galaxies produce the high gas densities that lead to sustained critical accretion rates and hence rapid growth commensurate with the existence of ∼ 10 9 M black holes as early as z ∼ 7. Here we use our newest, higher resolution cosmological hydrodynamic simulation, BlueTides (Feng et al 2016(Feng et al , 2015Waters et al 2016a,b) (covering a volume of [0.5 Gpc] 3 ) which includes improved prescriptions for star formation, as well as black hole accretion and associated feedback processes.…”

Clustering of intermediate redshift quasars using the final SDSS III-BOSS sample

“…Finally, models of how quasars populate dark matter halos, for instance, empirical approaches such as the halo occupation distribution framework (HOD; Seljak 2000; Peacock & Smith 2000;Benson et al 2000;Scoccimarro et al 2001;White, Hernquist & Springel 2001;Berlind & Weinberg 2002;Cooray & Sheth 2002, and references therein) have been successful in modeling galaxies at low redshift (e.g., Zheng et al 2005;Zheng, Coil & Zehavi 2007;Zehavi et al 2011), but are now being updated to model quasar clustering at different wavelengths and redshifts (e.g., Degraf et al 2011a;Richardson et al 2012;White et al 2012;Conroy & White 2013;Richardson et al 2013;Veale, White & Conroy 2014;Caplar, Lilly & Trakhtenbrot 2014). It is not clear to what extent such HOD models describe rare and heavily biased quasars at high redshift, and it is critical to push observations to z ∼ 3 as the most sophisticated hydrodynamic simulations being used to interpret the HOD are now being pushed from high redshift down to z < 4 (e.g., DeGraf et al 2012;Di Matteo et al 2012).…”

Bright vigorous winds as signposts of supermassive black hole birth

“…Although in principle there is plenty of gas available at high redshift and cold flows have been shown to be effective in bringing that gas down to the centre of (massive) halos (Di Matteo et al 2012), the conditions to avoid substantial fragmentations and to overcome the centrifugal barrier are not fully understood yet. Several possibilities have been discussed, c 2015 RAS such as the dissociation of H2 molecules by Lyman-Werner ionising radiation coming from nearby, star-forming galaxies in order to avoid cooling and fragmentation (Ferrara & Loeb 2013;Dijkstra, Ferrara & Mesinger 2014).…”