@article{31bfd5a16f734486af51243e4d68040d,
title = "The discovery of a high-redshift quasar without emission lines from sloan digital sky survey commissioning data",
abstract = "We report observations of a luminous unresolved object at redshift z = 4.62, with a featureless optical spectrum redward of the Lya forest region, discovered from Sloan Digital Sky Survey commissioning data. The redshift is determined by the onset of the Lya forest at Ao and a Lyman limit system at Ao l ∼ 6800 l = 5120. A strong Lya absorption system with weak metal absorption lines at z = 4.58 is also identified in the spectrum. The object has a continuum absolute magnitude of 226.6 at 1450 Ao in the rest frame (h = 0.5, ;= 0.5) and therefore 0 0 cannot be an ordinary galaxy. It shows no radio emission (the 3 j upper limit of its flux at 6 cm is 60 mJy), indicating a radio-to-optical flux ratio at least as small as that of the radio-weakest BL Lacertae objects known. It is also not linearly polarized to a 3 j upper limit of 4% in the observed I band. Therefore, it is either the most distant BL Lac object known to date, with very weak radio emission, or a new type of unbeamed quasar, whose broad emission line region is very weak or absent.",
keywords = "Quasars: individual (SDSS 1533200), Radio continuum: galaxies, X-rays: galaxies",
author = "Xiaohui Fan and Strauss, {Michael A.} and Gunn, {James E.} and Lupton, {Robert H.} and Carilli, {C. L.} and Rupen, {M. P.} and Schmidt, {Gary D.} and Moustakas, {Leonidas A.} and Marc Davis and James Annis and Bahcall, {Neta A.} and J. Brinkmann and Brunner, {Robert J.} and Istv{\'a}n Csabai and Mamoru Doi and Masataka Fukugita and Heckman, {Timothy M.} and Hennessy, {G. S.} and Hindsley, {Robert B.} and Z{\v e}ljko Ivezi{\'c} and Knapp, {G. R.} and Lamb, {D. Q.} and Munn, {Jeffrey A.} and Pauls, {A. George} and Pier, {Jeffrey R.} and M. Rockosi and Schneider, {Donald P.} and Szalay, {Alexander S.} and Tucker, {Douglas L.} and York, {Donald G.}",
note = "Funding Information: The SDSS22 is a joint project of the University of Chicago, Fermilab, the Institute for Advanced Study, the Japan Participation Group, Johns Hopkins University, the Max-Planck-Institute for Astronomy, Princeton University, the US Naval Observatory, and the University of Washington. Apache Point Observatory, site of the SDSS, is operated by the Astrophysical Research Consortium. Funding for the project has been provided by the Alfred P. Sloan Foundation, the SDSS member institutions, the National Aeronautics and Space Administration, the National Science Foundation, the US Department of Energy, and the Ministry of Education of Japan. X. F. and M. A. S. acknowledge additional support from the Research Corporation, NSF grant AST 96-16901, the Princeton University Research Board, and an Advisory Council Scholarship. We thank John Bahcall, Bruce Draine, Gordon Richards, Todd Tripp, Wolfgang Voges, and the referee, John Stocke, for useful discussions and comments and Russett McMillan for her usual expert help at the 3.5 m telescope. Publisher Copyright: {\textcopyright}1999. The American Astronomical Society. All rights reserved. Printed in U.S.A.",
year = "1999",
month = dec,
day = "1",
doi = "10.1086/312382/pdf",
language = "English (US)",
volume = "526",
pages = "L57--L60",
journal = "Astrophysical Journal Letters",
issn = "2041-8205",
publisher = "American Astronomical Society",
number = "2",
}