@article{ce471ed2faa1477fbf6eecb7588cd5c6,
title = "Characterizing the WISE-selected heavily obscured quasar population with optical spectroscopy from the Southern African Large Telescope",
abstract = "We present the results of an optical spectroscopic survey of 46 heavily obscured quasar candidates. Objects are selected using their mid-infrared (mid-IR) colours and magnitudes from the Wide-Field Infrared Survey Explorer (WISE) anzd their optical magnitudes from the Sloan Digital Sky Survey. Candidate Active Galactic Nuclei (AGNs) are selected to have mid-IR colours indicative of quasar activity and lie in a region of mid-IR colour space outside previously published X-ray based selection regions. We obtain optical spectra for our sample using the Robert Stobie Spectrograph on the Southern African Large Telescope. 30 objects (65 per cent) have identifiable emission lines, allowing for the determination of spectroscopic redshifts. Other than one object at z ~ 2.6, candidates have moderate redshifts ranging from z = 0.1 to 0.8 with a median of 0.3. 21 (70 per cent) of our objects with identified redshift (46 per cent of the whole sample) are identified as AGNs through common optical diagnostics. We model the spectral energy distributions of our sample and found that all require a strong AGN component, with an average intrinsic AGN fraction at 8 μm of 0.91. Additionally, the fits require large extinction coefficients with an average E(B - V)AGN = 17.8 (average A(V)AGN = 53.4). By focusing on the area outside traditional mid-IR photometric cuts, we are able to capture and characterize a population of deeply buried quasars that were previously unattainable through X-ray surveys alone.",
keywords = "Galaxies: active, Galaxies: distances and redshifts, Quasars: emission lines",
author = "Hviding, {Raphael E.} and Hickox, {Ryan C.} and Hainline, {Kevin N.} and Carroll, {Christopher M.} and DiPompeo, {Michael A.} and Wei Yan and Jones, {Mackenzie L.}",
note = "Funding Information: We would like to thank the anonymous referee for their constructive comments which improved the final paper. This work uses data taken from the Southern African Large Telescope. R.E.H. acknowledges support from the The James O. Freedman Presidential Scholars Program, the Dartmouth E.E. Just Program. R.C.H. acknowledges support from the National Science Foundation through grant number 1515364 and Faculty Early Career Development Program award 1554584, and from the National Aeronautics and Space Administration through grants NNX16AN48G and NNX15AP24G. This work makes use of data from the WISE which is a joint project of the University of California, Los Angeles and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This data makes use of data from the SDSS. Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the U.S. Department of Energy Office of Science. The SDSS-III web site is http://www.sdss3.org/. SDSS-III is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS-III Collaboration including the University of Arizona, the Brazilian Participation Group, Brookhaven National Laboratory, Carnegie Mellon University, University of Florida, the French Participation Group, the German Participation Group, Harvard University, the Instituto de Astrofisica de Canarias, the 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, NewMexico State University, New York University, Ohio State University, Pennsylvania State University, University of Portsmouth, Princeton University, the Spanish Participation Group, University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington and Yale University. This work makes use of data from United Kingdom InfraRed Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS). The UKIDSS project is defined in Lawrence et al. (2007). UKIDSS uses the UKIRT Wide Field Camera (WFCAM; Casali et al. 2007) and a photometric system described in Hewett et al. (2006). The pipeline processing and science archive is described in Hambly et al. (2008). Publisher Copyright: {\textcopyright} 2017 The Author(s).",
year = "2018",
month = feb,
day = "21",
doi = "10.1093/mnras/stx2849",
language = "English (US)",
volume = "474",
pages = "1955--1969",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "2",
}