Reinabelle Reyes et al. 2008 The Astronomical Journal 136 2373 doi:10.1088/0004-6256/136/6/2373
SPACE DENSITY OF OPTICALLY SELECTED TYPE 2 QUASARS
FREE ISSUEReinabelle Reyes1, Nadia L. Zakamska2,7, Michael A. Strauss1, Joshua Green1, Julian H. Krolik3, Yue Shen1, Gordon T. Richards4, Scott F. Anderson5 and Donald P. Schneider6
Show affiliationsType 2 quasars are luminous active galactic nuclei whose central regions are obscured by large amounts of gas and dust. In this paper, we present a catalog of type 2 quasars from the Sloan Digital Sky Survey, selected based on their optical emission lines. The catalog contains 887 objects with redshifts z < 0.83; this is 6 times larger than the previous version and is by far the largest sample of type 2 quasars in the literature. We derive the [O III]5007 luminosity function (LF) for 108.3 L 
< L [O III] < 1010 L (corresponding to intrinsic luminosities up to M[2500 Å] 
–28 mag or bolometric luminosities up to 4 × 1047 erg s–1). This LF provides robust lower limits to the actual space density of obscured quasars due to our selection criteria, the details of the spectroscopic target selection, and other effects. We derive the equivalent LF for the complete sample of type 1 (unobscured) quasars and determine the ratio of type 2 to type 1 quasar number densities. Our data constrain this ratio to be at least ~1.5:1 for 108.3 L < L [O III] < 109.5 L at z < 0.3, and at least ~1.2:1 for L [O III] ~ 1010 L at 0.3 < z < 0.83. Type 2 quasars are at least as abundant as type 1 quasars in the relatively nearby universe (z 
0.8) for the highest luminosities.
- Keywords
galaxies: active; quasars: emission lines; quasars: general; surveys
- Dates
-
Issue 6 (2008 December)
Received 2008 January 3, accepted for publication 2008 September 19
Published 2008 November 10
An Erratum for this article has been published in 2010 The Astronomical Journal 139 1295
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Space Density of Optically Selected Type 2 Quasars
Reinabelle Reyes et al. 2008 The Astronomical Journal 136 2373
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