Jiang, Linhua and Fan, Xiaohui and Bian, Fuyan and Annis, James and Chiu, Kuenley and Jester, Sebastian and Lin, Huan and Lupton, Robert H. and Richards, Gordon T. and Strauss, Michael A. and Malanushenko, Viktor and Malanushenko, Elena and Schneider, Donald P. (2009) A Survey of z ~ 6 Quasars in the Sloan Digital Sky Survey Deep Stripe. II. Discovery of Six Quasars at z AB>21. Astronomical Journal, 138 (1). pp. 305-311. ISSN 0004-6256 http://resolver.caltech.edu/CaltechAUTHORS:20090903-150019437
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We present the discovery of six new quasars at z ~ 6 selected from the Sloan Digital Sky Survey (SDSS) southern survey, a deep imaging survey obtained by repeatedly scanning a stripe along the celestial equator. The six quasars are about 2 mag fainter than the luminous z ~ 6 quasars found in the SDSS main survey and 1 mag fainter than the quasars reported in Paper I. Four of them comprise a complete flux-limited sample at 21 < z_(AB) < 21.8 over an effective area of 195 deg^2. The other two quasars are fainter than z_(AB) = 22 and are not part of the complete sample. The quasar luminosity function at z ~ 6 is well described as a single power law Φ(L_(1450))α L^β_(1450) over the luminosity range –28 < M_(1450) < –25. The best-fitting slope β varies from –2.6 to –3.1, depending on the quasar samples used, with a statistical error of 0.3-0.4. About 40% of the quasars discovered in the SDSS southern survey have very narrow Lyα emission lines, which may indicate small black hole masses and high Eddington luminosity ratios, and therefore short black hole growth timescales for these faint quasars at early epochs.
|Additional Information:||© 2009. The American Astronomical Society. Received 2009 March 8; accepted 2009 May 24; published 2009 June 11. We acknowledge supports from NSF grants AST-0307384 and AST-0806861 and a Packard Fellowship for Science and Engineering (L.J., X.F., and F.B.). X.F. also acknowledges support from Max Planck Society. M.A.S. acknowledges the support of NSF grant AST-0707266. We thank the MMT staff, Magellan staff, andKPNOstaff for their expert help in preparing and carrying out the observations. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSSWeb site is http://www.sdss.org/. The SDSS is managed by the Astrophysical Research Consortium for the Participating Institutions. The Participating Institutions are the American Museum of Natural History, Astrophysical Institute Potsdam, University of Basel, University of Cambridge, Case Western Reserve University, University of Chicago, Drexel University, Fermilab, the Institute for Advanced Study, the Japan Participation Group, Johns Hopkins University, the Joint Institute for Nuclear Astrophysics, the Kavli Institute for Particle Astrophysics and Cosmology, the Korean Scientist Group, the Chinese Academy of Sciences (LAMOST), Los Alamos National Laboratory, the Max-Planck-Institute for Astronomy (MPIA), the Max-Planck- Institute for Astrophysics (MPA), New Mexico State University, Ohio State University, University of Pittsburgh, University of Portsmouth, Princeton University, the United States Naval Observatory, and the University of Washington.|
|Subject Keywords:||cosmology: observations; quasars: emission lines; quasars: general|
|Official Citation:||A Survey of z ~ 6 Quasars in the Sloan Digital Sky Survey Deep Stripe. II. Discovery of Six Quasars at z AB>21 Linhua Jiang, Xiaohui Fan, Fuyan Bian, James Annis, Kuenley Chiu, Sebastian Jester, Huan Lin, Robert H. Lupton, Gordon T. Richards, Michael A. Strauss, Viktor Malanushenko, Elena Malanushenko, and Donald P. Schneider 2009 The Astronomical Journal 138 305-311 doi: 10.1088/0004-6256/138/1/305|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||08 Sep 2009 21:18|
|Last Modified:||26 Dec 2012 11:19|
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