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2007AJ....133.2222S -
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Astron. J., 133, 2222-2241 (2007/May-0)
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Clustering of high-redshift (z ≥ 2.9) quasars from the Sloan Digital Sky Survey.
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SHEN Y., STRAUSS M.A., OGURI M., HENNAWI J.F., FAN X., RICHARDS G.T., HALL P.B., GUNN J.E., SCHNEIDER D.P., SZALAY A.S., THAKAR A.R., VANDEN BERK D.E., ANDERSON S.F., BAHCALL N.A., CONNOLLY A.J. and KNAPP G.R.
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Abstract (from CDS):
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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 deg^{2} from the Fifth Data Release of the Sloan Digital Sky Survey. We fit a power-law to the projected correlation function w_{p}(r_{p}) to marginalize over redshift-space distortions and redshift errors. For a real-space correlation function of the form ξ(r)=(r/r_{0})^{–γ}, the fitted parameters in comoving coordinates are r_{0}=15.2±2.7 h^{–1} Mpc and γ=2.0±0.3, over a scale range 4 h^{–1} Mpc≤r_{p}≤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 r_{0}~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 r_{0}=16.9±1.7 h^{–1} Mpc for the former and r_{0}=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)x10^{12} h^{–1} *M*_{☉} for quasars with 2.9≤z≤3.5 and (4-6)x10^{12} h^{–1} *M*_{☉} for quasars with z≥3.5; the effective bias factor b_{eff} increases with redshift, e.g., b_{eff}∼8 at z=3.0 and b_{eff}∼16 at z=4.5.

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Abstract Copyright:
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∼

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Journal keyword(s):
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Cosmology: Observations - Cosmology: Large-Scale Structure of Universe - Galaxies: Quasars: General - Surveys
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VizieR on-line data:
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<Available at CDS (J/AJ/133/2222): table1.dat>

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Nomenclature:
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Table 1: [SSO2007] DDD.dddddd+DD.dddddd N=4426.

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Simbad objects:
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5884

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