A SURVEY of LUMINOUS HIGH-REDSHIFT QUASARS with SDSS and WISE. II. the BRIGHT END of the QUASAR LUMINOSITY FUNCTION at z ∼ 5

Jinyi Yang, Feige Wang, Xue Bing Wu, Xiaohui Fan, Ian D. McGreer, Fuyan Bian, Weimin Yi, Qian Yang, Yanli Ai, Xiaoyi Dong, Wenwen Zuo, Richard Green, Linhua Jiang, Shu Wang, Ran Wang, Minghao Yue

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

This is the second paper in a series on a new luminous z ∼ 5 quasar survey using optical and near-infrared colors. Here we present a new determination of the bright end of the quasar luminosity function (QLF) at z ∼ 5. Combining our 45 new quasars with previously known quasars that satisfy our selections, we construct the largest uniform luminous z ∼ 5 quasar sample to date, with 99 quasars in the range of 4.7 ≤ z < 5.4 and -29 < M 1450 ≤ -26.8, within the Sloan Digital Sky Survey (SDSS) footprint. We use a modified 1/V a method including flux limit correction to derive a binned QLF, and we model the parametric QLF using maximum likelihood estimation. With the faint-end slope of the QLF fixed as α = -2.03 from previous deeper samples, the best fit of our QLF gives a flatter bright end slope β = -3.58 ± 0.24 and a fainter break magnitude = -26.98 ± 0.23 than previous studies at similar redshift. Combined with previous work at lower and higher redshifts, our result is consistent with a luminosity evolution and density evolution model. Using the best-fit QLF, the contribution of quasars to the ionizing background at z ∼ 5 is found to be 18%-45% with a clumping factor C of 2-5. Our sample suggests an evolution of radio loud fraction with optical luminosity but no obvious evolution with redshift.

Original languageEnglish (US)
Article number33
JournalAstrophysical Journal
Volume829
Issue number1
DOIs
StatePublished - Sep 20 2016

Keywords

  • galaxies: active
  • galaxies: high-redshift
  • quasars: general

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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