Modelling the cosmological co-evolution of supermassive black holes and galaxies - II. The clustering of quasars and their dark environment

Abstract

We use semi-analytic modelling on top of the Millennium simulation to study the joint formation of galaxies and their embedded supermassive black holes. Our goal is to test scenarios in which black hole accretion and quasar activity are triggered by galaxy mergers, and to constrain different models for the light curves associated with individual quasar events. In the present work, we focus on studying the spatial distribution of simulated quasars. At all luminosities, we find that the simulated quasar two-point correlation function is fit well by a single power law in the range 0.5 less than or similar to r less than or similar to 20 h(-1) Mpc, but its normalization is a strong function of redshift. When we select only quasars with luminosities within the range typically accessible by today's quasar surveys, their clustering strength depends only weakly on luminosity, in agreement with observations. This holds independently of the assumed light-curve model, since bright quasars are black holes accreting close to the Eddington limit, and are hosted by dark matter haloes with a narrow mass range of a few 10(12) h(-1) M(circle dot). Therefore, the clustering of bright quasars cannot be used to disentangle light-curve models, but such a discrimination would become possible if the observational samples can be pushed to significantly fainter limits. Overall, our clustering results for the simulated quasar population agree rather well with observations, lending support to the conjecture that galaxy mergers could be the main physical process responsible for triggering black hole accretion and quasar activity

The cosmic growth of the active black hole population at 1 <z <2 in zCOSMOS, VVDS and SDSS

“…These models range from large cosmological hydrodynamic simulations (Degraf et al 2010;Khandai et al 2014;Hirschmann et al 2014;Sijacki et al 2014;Bachmann et al 2014, Rosas-Guevara et al, in preparation), semianalytical models (Cattaneo et al 2005;Marulli et al 2008;Bonoli et al 2009;Fanidakis et al 2012;Hirschmann et al 2012;Menci et al 2014;Neistein & Netzer 2014) to more phenomenological models (Wyithe & Loeb 2003;Shen 2009;Conroy & White 2013;Veale et al 2014;Caplar et al 2014). However, since these models differ in many details, in particular the trigger mechanisms for AGN activity, no consistent picture on the physics of BH growth can be inferred from these comparisons alone.…”

Dark-ages reionization and galaxy formation simulation – X. The small contribution of quasars to reionization

“…The assumption that black holes are either accreting at the Eddington rate ( = 1, see equation 16) or stay quiescent has been shown to provide a good description of black hole growth for the majority of black holes at high redshift (Bonoli et al 2009). …”

“…We note that one may recalibrate the model with a more efficient black hole growth rate at high redshift (e.g. by incorporating a redshift dependence in the equation 19, see Bonoli et al 2009), in order to match the G15 luminosity function and the estimated emissivity. Mitra et al (2015) also suggest that if G15 emissivity is correct, quasaronly reionization is possible and it results in a small value of τe due to the rapid evolution of the Lyman-limit systems.…”

“…8 As mergers drive strong gas inflows towards the central region (Capelo et al 2015), cold gas is funnelled to the central black hole of the resulting merged galaxy, significantly increasing its mass. The amount of accretion can be estimated by (Bonoli et al 2009;Croton et al 2016) ∆m bh,max = min…”

A unifying evolutionary framework for infrared-selected obscured and unobscured quasar host haloes

“…Lacy et al 2004;Treister et al 2004;Stern et al 2005;Hickox et al 2007Hickox et al , 2009Hickox et al , 2011Stern et al 2012;Hainline et al 2014;DiPompeo et al 2014b;Hickox et al 2014;Lacy et al 2015;DiPompeo et al 2015; that has historically been dominated by optically detected unobscured systems (e.g. Croom et al 2004Croom et al , 2005Richards et al 2006a,b;Myers et al 2007;Croom et al 2009;Ross et al 2009;Shen et al 2009;Bonoli et al 2009;Eftekharzadeh et al 2015). This has resulted in tension between the prevailing paradigms that attempt to explain the physical origin of observational quasar subclasses.…”