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Title: Discovery of eight z ∼ 6 quasars from Pan-STARRS1

High-redshift quasars are currently the only probes of the growth of supermassive black holes and potential tracers of structure evolution at early cosmic time. Here we present our candidate selection criteria from the Panoramic Survey Telescope and Rapid Response System 1 and follow-up strategy to discover quasars in the redshift range 5.7 ≲ z ≲ 6.2. With this strategy we discovered eight new 5.7 ≤ z ≤ 6.0 quasars, increasing the number of known quasars at z > 5.7 by more than 10%. We additionally recovered 18 previously known quasars. The eight quasars presented here span a large range of luminosities (–27.3 ≤ M {sub 1450} ≤ –25.4; 19.6 ≤ z {sub P1} ≤ 21.2) and are remarkably heterogeneous in their spectral features: half of them show bright emission lines whereas the other half show a weak or no Lyα emission line (25% with rest-frame equivalent width of the Lyα +N V line lower than 15 Å). We find a larger fraction of weak-line emission quasars than in lower redshift studies. This may imply that the weak-line quasar population at the highest redshifts could be more abundant than previously thought. However, larger samples of quasars are needed to increase themore » statistical significance of this finding.« less
Authors:
; ; ; ; ; ;  [1] ; ; ; ; ;  [2] ; ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [9] more »; « less
  1. Max Planck Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg (Germany)
  2. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
  3. Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States)
  4. School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States)
  5. Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)
  6. MIT-Kavli Center for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)
  7. Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69 D-53121 Bonn (Germany)
  8. Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)
  9. Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching (Germany)
Publication Date:
OSTI Identifier:
22342299
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (New York, N.Y. Online); Journal Volume: 148; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BLACK HOLES; COSMOLOGY; EMISSION; EVOLUTION; GROWTH; LUMINOSITY; QUASARS; RED SHIFT; TELESCOPES