A SURVEY OF LUMINOUS HIGH-REDSHIFT QUASARS WITH SDSS AND WISE . II. THE BRIGHT END OF THE QUASAR LUMINOSITY FUNCTION AT z ∼ 5

• Main Authors: Yang, Jinyi, Wang, Feige, Wu, Xue-Bing, Fan, Xiaohui, McGreer, Ian D., Bian, Fuyan, Yi, Weimin, Yang, Qian, Ai, Yanli, Dong, Xiaoyi, Zuo, Wenwen, Green, Richard, Jiang, Linhua, Wang, Shu, Wang, Ran, Yue, Minghao
• Other Authors: Univ Arizona, Steward Observ
• Language: en
• Published: IOP PUBLISHING LTD 2016
• Subjects: galaxies: active; galaxies: high-redshift; quasars: general
• Online Access: http://hdl.handle.net/10150/621976; http://arizona.openrepository.com/arizona/handle/10150/621976

This is the second paper in a series on a new luminous z similar to 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 similar to 5. Combining. our 45 new quasars with previously known quasars that satisfy our selections, we construct the largest uniform luminous z similar to 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 alpha = -2.03 from previous deeper samples, the best fit of our QLF gives a flatter bright end slope beta = -3.58 +/- 0.24 and a fainter break magnitude M-1450(*) = -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 similar to 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.