Filling in the Quasar Redshift Gap at z ∼ 5.5. II. A Complete Survey of Luminous Quasars in the Post-reionization Universe

Yang, Jinyi; Wang, Feige; Fan, Xiaohui; Wu, Xue-Bing; Bian, Fuyan; Ba�ados, Eduardo; Yue, Minghao; Schindler, Jan-Torge; Yang, Qian; Jiang, Linhua; McGreer, Ian D.; Green, Richard; Dye, Simon

Abstract

We present the final results from our survey of luminous z ~ 5.5 quasars. This is the first systematic quasar survey focusing on quasars at z ~ 5.5, during the post-reionization epoch. It has been challenging to select quasars at 5.3 < z < 5.7 using conventional color selections, due to their similar optical colors to those of late-type stars, especially M dwarfs. We developed a new selection technique for z ~ 5.5 quasars based on optical, near-infrared (IR), and mid-IR photometry, using data from the Sloan Digital Sky Survey (SDSS), PanSTARR1 (PS1), the UKIRT Infrared Deep Sky Surveys–Large Area Survey, the UKIRT Hemisphere Survey, the VISTA Hemisphere Survey, and the Wide Field Infrared Survey Explorer, covering ~11,000 deg2 of high galactic latitude sky. In this paper, we present the discovery of 15 new quasars at 5.22 ≤ z ≤ 5.78. Together with results from Yang et al., our survey provides a complete, flux-limited sample of 31 quasars at 5.3 ≤ z ≤ 5.7. We measure the quasar spatial density at z ~ 5.5 and M 1450 < −26.2. Our result is consistent with the rapid decline of the quasar spatial density from z = 5 to 6, with k = −0.66 ± 0.05 (ρ(z) ∝ 10 kz ). In addition, we present a new survey using optical colors only from the full PS1 area for luminous quasars at z = 5.0–5.5, which is beyond the SDSS footprint, and report the preliminary results from this survey, including 51 new quasars discovered at 4.61 ≤ z ≤ 5.71.

Citation

Yang, J., Wang, F., Fan, X., Wu, X.-B., Bian, F., Bañados, E., Yue, M., Schindler, J.-T., Yang, Q., Jiang, L., McGreer, I. D., Green, R., & Dye, S. (2019). Filling in the Quasar Redshift Gap at z ∼ 5.5. II. A Complete Survey of Luminous Quasars in the Post-reionization Universe. Astrophysical Journal, 871(2), 199. https://doi.org/10.3847/1538-4357/aaf858

• Journal Article Type: Article
• Acceptance Date: Dec 11, 2018
• Online Publication Date: Jan 31, 2019
• Publication Date: Feb 1, 2019
• Deposit Date: Feb 8, 2019
• Publicly Available Date: Feb 11, 2019
• Journal: The Astrophysical Journal
• Print ISSN: 0004-637X
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 871
• Issue: 2
• Article Number: 199
• Pages: 199
• DOI: https://doi.org/10.3847/1538-4357/aaf858
• Public URL: https://nottingham-repository.worktribe.com/output/1529413
• Publisher URL: https://iopscience.iop.org/article/10.3847/1538-4357/aaf858/meta
• Additional Information: Journal title: The Astrophysical Journal; Article type: paper; Article title: Filling in the Quasar Redshift Gap at z ∼ 5.5. II. A Complete Survey of Luminous Quasars in the Post-reionization Universe; Copyright information: © 2019. The American Astronomical Society. All rights reserved.; Date received: 2018-10-28; Date accepted: 2018-12-11; Online publication date: 2019-01-31
• Contract Date: Feb 11, 2019