A survey of z> 5.7 quasars in the sloan digital sky survey. IV. Discovery of seven additional quasars

Xiaohui Fan, Michael A. Strauss, Gordon T. Richards, Joseph F. Hennawi, Robert H. Becker, Richard L. White, Aleksandar M. Diamond-Stanic, Jennifer L. Donley, Linhua Jiang, J. Serena Kim, Marianne Vestergaard, Jason E. Young, James E. Gunn, Robert H. Lupton, Gillian R. Knapp, Donald P. Schneider, W. N. Brandt, Neta A. Bahcall, J. C. Barentine, J. BrinkmannHoward J. Brewington, Masataka Fukugita, Michael Harvanek, S. J. Kleinman, Jurek Krzesinski, Dan Long, Eric H. Neilsen, Atsuko Nitta, Stephanie A. Snedden, Wolfgang Voges

Research output: Contribution to journalReview articlepeer-review

358 Scopus citations


We present the discovery of seven quasars at z > 5.7, selected from ∼2000 deg 2 of multicolor imaging data of the Sloan Digital Sky Survey. The new quasars have redshifts z from 5.79 to 6.13. Five are selected as part of a complete flux-limited sample in the SDSS northern Galactic cap; two have larger photometric errors and are not part of the complete sample. One of the new quasars, SDSS J1335+3533 (z = 5.93), exhibits no emission lines; the 3 σ limit on the rest-frame equivalent width of the Lyα+N v line is 5 Å. It is the highest redshift lineless quasar known and could be a gravitational lensed galaxy, a BL Lac object, or a new type of quasar. Two new z > 6 quasars, SDSS 1250+3130 (z = 6.13) and SDSS J1137+3549(z = 6.01), show deep Gunn-Peterson absorption gaps in Lyα. These gaps are narrower than the complete Gunn-Peterson absorption troughs observed among quasars at z > 6.2 and do not have complete Lyß absorption.

Original languageEnglish (US)
Pages (from-to)1203-1209
Number of pages7
JournalAstronomical Journal
Issue number3
StatePublished - Mar 2006


  • Quasars: absorption lines
  • Quasars: emission lines
  • Quasars: general

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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