TY - JOUR
T1 - Exploring Reionization-era Quasars. IV. Discovery of Six New z ⪆ 6.5 Quasars with DES, VHS, and unWISE Photometry
AU - Yang, Jinyi
AU - Wang, Feige
AU - Fan, Xiaohui
AU - Yue, Minghao
AU - Wu, Xue Bing
AU - Li, Jiang Tao
AU - Bian, Fuyan
AU - Jiang, Linhua
AU - Bañados, Eduardo
AU - Beletsky, Yuri
N1 - Publisher Copyright:
© 2019. The American Astronomical Society. All rights reserved.
PY - 2019
Y1 - 2019
N2 - This is the fourth paper in a series of publications aiming at discovering quasars at the epoch of reionization. In this paper, we expand our search for z ∼ 7 quasars to the footprint of the Dark Energy Survey (DES) Data Release One (DR1), covering ∼5000 deg2 of a new area. We select z ∼ 7 quasar candidates using deep optical, near-infrared (near-IR) and mid-infrared (mid-IR) photometric data from the DES DR1, the VISTA Hemisphere Survey, the VISTA Kilo-degree Infrared Galaxy survey, the UKIRT InfraRed Deep Sky Surveys - Large Area Survey (ULAS), and the unblurred coadds from the Wide-field Infrared Survey Explore (WISE) images (unWISE). The inclusion of DES and unWISE photometry allows the search to reach ∼1 mag fainter, comparing to our z ⪆ 6.5 quasar survey in the northern sky. We report the initial discovery and spectroscopic confirmation of six new luminous quasars at z > 6.4, including an object at z = 7.02, the fourth quasar yet known at z > 7, from a small fraction of candidates observed thus far. Based on the recent measurement of z ∼ 6.7 quasar luminosity function using the quasar sample from our survey in the northern sky, we estimate that there will be ⪆55 quasars at z > 6.5 at M 1450 < -24.5 in the full DES footprint.
AB - This is the fourth paper in a series of publications aiming at discovering quasars at the epoch of reionization. In this paper, we expand our search for z ∼ 7 quasars to the footprint of the Dark Energy Survey (DES) Data Release One (DR1), covering ∼5000 deg2 of a new area. We select z ∼ 7 quasar candidates using deep optical, near-infrared (near-IR) and mid-infrared (mid-IR) photometric data from the DES DR1, the VISTA Hemisphere Survey, the VISTA Kilo-degree Infrared Galaxy survey, the UKIRT InfraRed Deep Sky Surveys - Large Area Survey (ULAS), and the unblurred coadds from the Wide-field Infrared Survey Explore (WISE) images (unWISE). The inclusion of DES and unWISE photometry allows the search to reach ∼1 mag fainter, comparing to our z ⪆ 6.5 quasar survey in the northern sky. We report the initial discovery and spectroscopic confirmation of six new luminous quasars at z > 6.4, including an object at z = 7.02, the fourth quasar yet known at z > 7, from a small fraction of candidates observed thus far. Based on the recent measurement of z ∼ 6.7 quasar luminosity function using the quasar sample from our survey in the northern sky, we estimate that there will be ⪆55 quasars at z > 6.5 at M 1450 < -24.5 in the full DES footprint.
KW - galaxies: active
KW - galaxies: high-redshift
KW - quasars: emission lines
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U2 - 10.3847/1538-3881/ab1be1
DO - 10.3847/1538-3881/ab1be1
M3 - Article
AN - SCOPUS:85068995745
SN - 0004-6256
VL - 157
JO - Astronomical Journal
JF - Astronomical Journal
IS - 6
M1 - 236
ER -