MODERATE Civ ABSORBER SYSTEMS REQUIRE 1012M

Abstract

We measure the two-point cross-correlation function of C iv absorber systems and quasars, using spectroscopic data from the Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic Survey (BOSS; Data Release 9). The 19,701 quasars and 6149 Civ “moderate” absorbers, 0.28Å<rest-frame equivalent width (EW)<5Å, in our study cover a redshift range of 2.1 < z < 2.5 over 3300 deg2 and represent a factor of two increase in sample size over previous investigations.We find a correlation scale length and slope of the redshift-space cross-correlation function of s0 = 8.46 ± 1.24 Mpc, γ = 1.68 ± 0.19, in the redshift-space range 10 < s < 100 Mpc. We find a projected cross-correlation function of C iv absorption systems and quasars of r0 = 7.76 ± 2.80 Mpc, γ = 1.74 ± 0.21. We measure the combined quasar and C iv bias to be bQSObCiv = 8.81 ± 2.28. Using an estimate of bQSO from the quasar auto-correlation function we find bCiv = 2.38 ± 0.62. This bC iv implies that EW > 0.28Å C iv absorbers at z ∼ 2.3 are typically found in dark matter halos that have masses 1011.3–1013.4M at that redshift. The complete BOSS sample will triple the number of both quasars and absorption systems and increase the power of this cross-correlation measurement by a factor of two.