Date Published:

April 1, 2015

Abstract:

We study the dependence of quasar clustering on quasar luminosity andblack hole mass by measuring the angular overdensity of photometricallyselected galaxies imaged by the Wide-field Infrared Survey Explorer(WISE) about z ˜ 0.8 quasars from SDSS. By measuring thequasar-galaxy cross-correlation function and using photometricallyselected galaxies, we achieve a higher density of tracer objects and amore sensitive detection of clustering than measurements of the quasarautocorrelation function. We test models of quasar formation andevolution by measuring the luminosity dependence of clusteringamplitude. We find a significant overdensity of WISE galaxies about z˜ 0.8 quasars at 0.2-6.4 h^-1 Mpc in projectedcomoving separation. We find no appreciable increase in clusteringamplitude with quasar luminosity across a decade in luminosity, and apower-law fit between luminosity and clustering amplitude gives anexponent of -0.01 ± 0.06 (1 σ error). We also fail tofind a significant relationship between clustering amplitude and blackhole mass, although our dynamic range in true mass is suppressed due tothe large uncertainties in virial black hole mass estimates. Our resultsindicate that a small range in host dark matter halo mass maps to alarge range in quasar luminosity.

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