| Title | Clustering of High-Redshift (z >= 2.9) Quasars from the Sloan Digital Sky Survey |
| Authors | Shen, Yue; Strauss, Michael A.; Oguri, Masamune; Hennawi, Joseph F.; Fan, Xiaohui; Richards, Gordon T.; Hall, Patrick B.; Gunn, James E.; Schneider, Donald P.; Szalay, Alexander S.; Thakar, Anirudda R.; Vanden Berk, Daniel E.; Anderson, Scott F.; Bahcall, Neta A.; Connolly, Andrew J.; Knapp, Gillian R. |
| Bibcode | 2007AJ....133.2222S Search ADS ↗ |
| Abstract | We study the two-point correlation function of a uniformly selected sample of 4426 luminous optical quasars with redshift 2.9<=z<=5.4 selected over 4041 deg2 from the Fifth Data Release of the Sloan Digital Sky Survey. We fit a power-law to the projected correlation function wp(rp) to marginalize over redshift-space distortions and redshift errors. For a real-space correlation function of the form ξ(r)=(r/r0)-γ, the fitted parameters in comoving coordinates are r0=15.2+/-2.7 h-1 Mpc and γ=2.0+/-0.3, over a scale range 4 h-1 Mpc<=rp<=150 h-1 Mpc. Thus high-redshift quasars are appreciably more strongly clustered than their z~1.5 counterparts, which have a comoving clustering length r0~6.5 h-1 Mpc. Dividing our sample into two redshift bins, 2.9<=z<=3.5 and z>=3.5, and assuming a power-law index γ=2.0, we find a correlation length of r0=16.9+/-1.7 h-1 Mpc for the former and r0=24.3+/-2.4 h-1 Mpc for the latter. Strong clustering at high redshift indicates that quasars are found in very massive, and therefore highly biased, halos. Following Martini & Weinberg, we relate the clustering strength and quasar number density to the quasar lifetimes and duty cycle. Using the Sheth & Tormen halo mass function, the quasar lifetime is estimated to lie in the range ~4-50 Myr for quasars with 2.9<=z<=3.5, and ~30-600 Myr for quasars with z>=3.5. The corresponding duty cycles are ~0.004-0.05 for the lower redshift bin and ~0.03-0.6 for the higher redshift bin. The minimum mass of halos in which these quasars reside is (2-3)×1012 h-1 Msolar for quasars with 2.9<=z<=3.5 and (4-6)×1012 h-1 Msolar for quasars with z>=3.5 the effective bias factor beff increases with redshift, e.g., beff~8 at z=3.0 and beff~16 at z=4.5. |
| Objects | 5884 Objects Search NED ↙ |
