2020/04/16 by Keven Ren, Michele Trenti, Tiziana Di Matteo
Physics and Astronomy · #Astronomy and Astrophysical Research #Black hole (networking) #Dark matter #Galaxies: Formation, Evolution, Phenomena #Halo #Halo mass function #Luminosity #Luminosity function #Quasar #Redshift #Scientific Research and Discoveries #astro-ph.GA
paper · pdf · doi:10.3847/1538-4357/ab86ab
12 pages, 6 figures; accepted for publication in ApJ
arxiv created 2020/04/16 · openalex created_date 2020/04/24 · openalex publication_date 2020/05/01 · arxiv updated 2020/05/20 · openalex updated_date 2026/08/05
Abstract The quasar luminosity function (QLF) offers insight into the early coevolution of black holes and galaxies. It has been characterized observationally up to redshift z ∼ 6 with clear evidence of a double power-law shape, in contrast to the Schechter-like form of the underlying dark-matter halo mass function. We investigate a physical origin for the difference in these distributions by considering the impact of stochasticity induced by the processes that determine the quasar luminosity for a given host halo and redshift. We employ a conditional luminosity function and construct the relation between median quasar magnitude versus halo mass with log-normal in luminosity scatter Σ, and duty-cycle ϵ DC , and focus on high redshift z ≳ 4. We show that, in order to reproduce the observed QLF, the Σ = 0 abundance matching requires all of the brightest quasars to be hosted in the rarest most massive dark-matter halos (with an increasing in halo mass). Conversely, for Σ > 0 the brightest quasars can be overluminous outliers hosted in relatively common dark-matter halos. In this case, the median quasar magnitude versus halo mass relation, M UV,c , flattens at the high-end, as expected in self-regulated growth due to feedback. We sample the parameter space of Σ and ϵ DC and show that M UV,c flattens above for . Models with ϵ DC ∼ 1 instead require a high mass threshold close to . We investigate the impact of ϵ DC and Σ on measurements of clustering and find there is no luminosity dependence on clustering for Σ > 0.3, consistent with recent observations from Subaru HSC.