Journal
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Volume 435, Issue 4, Pages 3306-3325Publisher
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stt1500
Keywords
quasars: emission lines; quasars: general
Categories
Funding
- Alfred P. Sloan Foundation
- National Science Foundation
- US Department of Energy Office of Science
- University of Arizona
- Brazilian Participation Group
- Brookhaven National Laboratory
- University of Cambridge
- Carnegie Mellon University
- University of Florida
- French Participation Group
- German Participation Group
- Harvard University
- Instituto de Astrofisica de Canarias
- Michigan State/Notre Dame/JINA Participation Group
- Johns Hopkins University
- Lawrence Berkeley National Laboratory
- Max Planck Institute for Astrophysics
- Max Planck Institute for Extraterrestrial Physics
- New Mexico State University
- New York University
- Ohio State University
- Pennsylvania State University
- University of Portsmouth
- Princeton University
- Spanish Participation Group
- University of Tokyo
- University of Utah
- Vanderbilt University
- University of Virginia
- University of Washington
- Yale University
- NSF [AST-0707266, AST-1108604]
- Theodore Dunham, Jr, Grant of the Fund for Astrophysical Research
- NASA ADAP [NNX10AC99G]
- National Aeronautics and Space Administration
Ask authors/readers for more resources
At low redshifts, dust-obscured quasars often have strong yet narrow permitted lines in the rest-frame optical and ultraviolet, excited by the central active nucleus, earning the designation type II quasars. We present a sample of 145 candidate type II quasars at redshifts between 2 and 4.3, encompassing the epoch at which quasar activity peaked in the universe. These objects, selected from the quasar sample of the Baryon Oscillation Spectroscopic Survey of the Sloan Digital Sky Survey III, are characterized by weak continuum in the rest-frame ultraviolet (typical continuum magnitude of i approximate to 22) and strong lines of C iv and Ly alpha, with full width at half-maximum less than 2000 km s(-1). The continuum magnitudes correspond to an absolute magnitude of -23 or brighter at redshift 3, too bright to be due exclusively to the host galaxies of these objects. Roughly one third of the objects are detected in the shorter wavelength bands of the Wide-Field Infrared Survey Explorer survey; the spectral energy distributions of these objects appear to be intermediate between classic type I and type II quasars seen at lower redshift. Five objects are detected at rest frame 6 mu m by Spitzer, implying bolometric luminosities of several times 10(46) erg s(-1). We have obtained polarization measurements for two objects; they are roughly 3 per cent polarized. We suggest that these objects are luminous quasars, with modest dust extinction (A(V) similar to 0.5 mag), whose ultraviolet continuum also includes a substantial scattering contribution. Alternatively, the line of sight to the central engines of these objects may be obscured by optically thick material whose covering fraction is less than unity.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available