The SDSS-III Baryon Oscillation Spectroscopic Survey: The Quasar Luminosity Function from Data Release Nine
Abstract
We present a new measurement of the optical Quasar Luminosity Function (QLF), using data from the Sloan Digital Sky Survey-III: Baryon Oscillation Spectroscopic Survey (SDSS-III: BOSS). From the SDSS-III Data Release Nine (DR9), we select a uniform sample of 22,301 i<=21.8 quasars over an area of 2236 sq. deg with confirmed spectroscopic redshifts between 2.2<z<3.5, filling in a key part of the luminosity-redshift plane for optical quasar studies. We derive the completeness of the survey through simulated quasar photometry, and check this completeness estimate using a sample of quasars selected by their photometric variability within the BOSS footprint. We investigate the level of systematics associated with our quasar sample using the simulations, in the process generating color-redshift relations and a new quasar k-correction. We probe the faint end of the QLF to M_i(z=2.2) = -24.5 and see a clear break in the QLF at all redshifts up to z=3.5. We find that a log-linear relation (in log[Phi*] - M*) for a luminosity and density evolution (LEDE) model adequately describes our data within the range 2.2<z<3.5; across this interval the break luminosity increases by a factor of ~2.3 while Phi* declines by a factor of ~6. At z<2.2 our data is reasonably well fit by a pure luminosity evolution (PLE) model. We see only a weak signature of "AGN downsizing", in line with recent studies of the hard X-ray luminosity function. We compare our measured QLF to a number of theoretical models and find that models making a variety of assumptions about quasar triggering and halo occupation can fit our data over a wide range of redshifts and luminosities.
Keywords
Cite
@article{arxiv.1210.6389,
title = {The SDSS-III Baryon Oscillation Spectroscopic Survey: The Quasar Luminosity Function from Data Release Nine},
author = {Nicholas P. Ross and Ian D. McGreer and Martin White and Gordon T. Richards and Adam D. Myers and Nathalie Palanque-Delabrouille and Michael A. Strauss and Scott F. Anderson and Yue Shen and W. N. Brandt and Christophe Yeche and Molly E. C. Swanson and Eric Aubourg and Stephen Bailey and Dmitry Bizyaev and Jo Bovy and Howard Brewington and J. Brinkmann and Colin DeGraf and Tiziana Di Matteo and Garrett Ebelke and Xiaohui Fan and Jian Ge and Elena Malanushenko and Viktor Malanushenko and Rachel Mandelbaum and Claudia Maraston and Demitri Muna and Daniel Oravetz and Kaike Pan and Isabelle Paris and Patrick Petitjean and Kevin Schawinski and David J. Schlegel and Donald P. Schneider and John D. Silverman and Audrey Simmons and Stephanie Snedden and Alina Streblyanska and Nao Suzuki and David H. Weinberg and Donald York},
journal= {arXiv preprint arXiv:1210.6389},
year = {2015}
}
Comments
28 pages, 19 figures, 9 tables. Submitted to The ApJ. All the necessary data and code used herein will be made publicly available at http://www.sdss3.org/dr9/qlf