The clustering of intermediateredshift quasars as measured by the Baryon Oscillation Spectroscopic Survey
Abstract
We measure the quasar twopoint correlation function over the redshift range 2.2 < z < 2.8 using data from the Baryon Oscillation Spectroscopic Survey. We use a homogeneous subset of the data consisting of 27 129 quasars with spectroscopic redshifts  by far the largest such sample used for clustering measurements at these redshifts to date. The sample covers 3600 deg^{2}, corresponding to a comoving volume of 9.7 (h^{1} Gpc)^{3} assuming a fiducial Λ cold dark matter cosmology, and it has a median absolute iband magnitude of 26, kcorrected to z= 2. After accounting for redshift errors we find that the redshiftspace correlation function is fitted well by a power law of slope 2 and amplitude s_{0}= (9.7 ± 0.5) h^{1} Mpc over the range 3 < s < 25 h^{1} Mpc. The projected correlation function, which integrates out the effects of peculiar velocities and redshift errors, is fitted well by a power law of slope 1 and r_{0}= (8.4 ± 0.6) h^{1} Mpc over the range 4 < R < 16 h^{1} Mpc. There is no evidence for strong luminosity or redshift dependence to the clustering amplitude, in part because of the limited dynamic range in our sample. Our results are consistent with, but more precise than, previous measurements at similar redshifts. Our measurement of the quasar clustering amplitude implies a bias factor of b≃ 3.5 for our quasar sample. We compare the data to models to constrain the manner in which quasars occupy dark matter haloes at z∼ 2.4 and infer that such quasars inhabit haloes with a characteristic mass of <M>≃ 10^{12} h^{1} M_{☉} with a duty cycle for the quasar activity of 1 per cent.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 August 2012
 DOI:
 10.1111/j.13652966.2012.21251.x
 arXiv:
 arXiv:1203.5306
 Bibcode:
 2012MNRAS.424..933W
 Keywords:

 quasars: general;
 cosmology: observations;
 largescale structure of Universe;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 20 pages, 18 figures. Minor modifications to match version accepted by journal