Discovery of eight z ∼ 6 quasars from Pan-STARRS1
- Max Planck Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg (Germany)
- Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
- Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States)
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States)
- Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)
- MIT-Kavli Center for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)
- Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69 D-53121 Bonn (Germany)
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)
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 the statistical significance of this finding.
- OSTI ID:
- 22342299
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 148, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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