A Direct Measurement of the Mean Occupation Function of Quasars: Breaking Degeneracies between Halo Occupation Distribution Models

Abstract

Recent work on quasar clustering suggests a degeneracy in the halo occupation distribution constrained from two-point correlation functions. To break this degeneracy, we make the first empirical measurement of the mean occupation function (MOF) of quasars at $z\sim 0.2$ by matching quasar positions with groups and clusters identified in the MaxBCG sample. We fit two models to the MOF, a power law and a 4-parameter model. The number distribution of quasars in host halos is close to Poisson, and the slopes of the MOF obtained from our best-fit models (for the power law case) favor a MOF that monotonically increases with halo mass. The best-fit slopes are $0.53\pm 0.04$ and $1.03\pm 1.12$ for the power law model and the 4-parameter model, respectively. We measure the radial distribution of quasars within dark matter halos and find it to be adequately described by a power law with a slope $-2.3\pm 0.4$. We measure the conditional luminosity function (CLF) of quasars and show that there is no evidence that quasar luminosity depends on host halo mass, similar to the inferences drawn from clustering measurements. We also measure the conditional black hole mass function (CMF) of our quasars. Although the results are consistent with no dependence on halo mass, we observe a slight indication of downsizing of the black hole mass function. The lack of halo mass dependence in the CLF and CMF shows that quasars residing in galaxy clusters have characteristic luminosity and black hole mass scales.

Matches the ApJ accepted version (11 pages, 8 figures)

References in corpus (17)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• A Catalog of Quasar Properties from SDSS DR7
• A luminous quasar at a redshift of z = 7.085
• Direct cosmological simulations of the growth of black holes and galaxies
• Clustering of High Redshift ($z\ge 2.9$) Quasars from the Sloan Digital Sky Survey
• The 2dF-SDSS LRG and QSO Survey: QSO clustering and the L-z degeneracy
• Clustering Analyses of 300,000 Photometrically Classified Quasars--I. Luminosity and Redshift Evolution in Quasar Bias
• Clustering Analyses of 300,000 Photometrically Classified Quasars--II. The Excess on Very Small Scales
• Quasar Clustering at $25\kpch$ from a Complete Sample of Binaries
• Radio Sources in Galaxy Clusters: Radial Distribution, and 1.4 GHz and K-band Bivariate Luminosity Function
• The Co-Formation of Spheroids and Quasars Traced in their Clustering
• The Distribution of AGN in Clusters of Galaxies
• Supermassive Black Holes in the Hierarchical Universe: A General Framework and Observational Tests
• The clustering of radio galaxies at z~0.55 from the 2SLAQ LRG survey
• Supermassive Black Holes and Their Environments
• Luminous Red Galaxy Population in Clusters at $0.2\le z\le 0.6$
• Dynamical friction of radio galaxies in galaxy clusters

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