The Diversity of Environments Around Luminous Quasars at Redshift $z\sim 6$

Abstract

Significant clustering around the rarest luminous quasars is a feature predicted by dark matter theory combined with number density matching arguments. However, this expectation is not reflected by observations of quasars residing in a diverse range of environments. Here, we assess the tension in the diverse clustering of visible $i$-band dropout galaxies around luminous $z\sim 6$ quasars. Our approach uses a simple empirical method to derive the median luminosity to halo mass relation, $L_c(M_h)$ for both quasars and galaxies under the assumption of log-normal luminosity scatter, ${\Sigma }_Q$ and ${\Sigma }_G$. We show that higher ${\Sigma }_Q$ reduces the average halo mass hosting a quasar of a given luminosity, thus introducing at least a partial reversion to the mean in the number count distribution of nearby Lyman-Break galaxies. We generate a large sample of mock Hubble Space Telescope fields-of-view centred across rare $z\sim 6$ quasars by resampling pencil beams traced through the dark matter component of the BlueTides cosmological simulation. We find that diverse quasar environments are expected for ${\Sigma }_Q>0.4$, consistent with numerous observations and theoretical studies. However, we note that the average number of galaxies around the central quasar is primarily driven by galaxy evolutionary processes in neighbouring halos, as embodied by our parameter ${\Sigma }_G$, instead of a difference in the large scale structure around the central quasar host, embodied by ${\Sigma }_Q$. We conclude that models with ${\Sigma }_G>0.3$ are consistent with current observational constraints on high-z quasars, and that such a value is comparable to the scatter estimated from hydrodynamical simulations of galaxy formation.

19 pages, 8 figures; accepted for publication in ApJ

References in corpus (18)

• UV Luminosity Functions at redshifts z~4 to z~10: 10000 Galaxies from HST Legacy Fields
• Clustering of High Redshift ($z\ge 2.9$) Quasars from the Sloan Digital Sky Survey
• Pōniuā'ena: A Luminous $z=7.5$ Quasar Hosting a 1.5 Billion Solar Mass Black Hole
• Formation of z ~ 6 quasars from hierarchical galaxy mergers
• LCDM predictions for galaxy protoclusters I: the relation between galaxies, protoclusters and quasars at z~6
• The origin of most massive black holes at high-z: BLUETIDES and the next quasar frontier
• The Habitat Segregation between Lyman Break Galaxies and Lyman alpha Emitters around a QSO at z~5
• The primordial environment of super massive black holes: large scale galaxy overdensities around $z\sim 6$ QSOs with LBT
• No overdensity of Lyman Alpha Emitting Galaxies around a quasar at z~5.7
• Black hole obscuration and duty cycles mediated by AGN feedback in high redshift galaxies
• The descendants of the first quasars in the BlueTides simulation
• The Brightest Galaxies at Cosmic Dawn from Scatter in the Galaxy Luminosity versus Halo Mass Relation
• Active Galactic Nucleus Environments and Feedback to Neighboring Galaxies at $z\sim 5$ Probed by Lyman-Alpha Emitters
• Black hole clustering and duty cycles in the Illustris simulation
• Comparing Simple Quasar Demographics Models
• The clustering of $z>7$ galaxies: Predictions from the BLUETIDES simulation
• On the Prevalence of Super-Massive Black Holes over Cosmic Time
• Stochastic Processes as the Origin of the Double-Power Law Shape of the Quasar Luminosity Function

Cited by in corpus (1)

• The need for obscured supermassive black hole growth to explain quasar proximity zones in the epoch of reionization