A survey of luminous high-redshift quasars with SDSS and Wise. II. The bright end of the quasar luminosity function at z ∼ 5
- Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China)
- Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
- Research School of Astronomy and Astrophysics, Australian National University, Weston Creek, ACT 2611 (Australia)
- Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China)
- School of Astronomy and Space Science, Sun Yat-Sen University, Guangzhou 510275 (China)
- Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030 (China)
- Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)
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 {sub 1450} ≤ −26.8, within the Sloan Digital Sky Survey (SDSS) footprint. We use a modified 1/V {sub 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 M{sub 1450}{sup ∗} = −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.
- OSTI ID:
- 22868678
- Journal Information:
- Astrophysical Journal, Vol. 829, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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