Characterizing the WISE-selected heavily obscured quasar population with optical spectroscopy from the Southern African Large Telescope
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. Candi...
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ndltd-arizona.edu-oai-arizona.openrepository.com-10150-6271402018-03-30T03:00:28Z Characterizing the WISE-selected heavily obscured quasar population with optical spectroscopy from the Southern African Large Telescope Hviding, Raphael E. Hickox, Ryan C. Hainline, Kevin N. Carroll, Christopher M. DiPompeo, Michael A. Yan, Wei Jones, Mackenzie L. Univ Arizona, Steward Observ galaxies: active galaxies: distances and redshifts quasars: emission lines 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 similar to 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 mu m 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. 2018-02 Article Characterizing the WISE-selected heavily obscured quasar population with optical spectroscopy from the Southern African Large Telescope 2018, 474 (2):1955 Monthly Notices of the Royal Astronomical Society 0035-8711 1365-2966 10.1093/mnras/stx2849 http://hdl.handle.net/10150/627140 http://arizona.openrepository.com/arizona/handle/10150/627140 Monthly Notices of the Royal Astronomical Society en http://academic.oup.com/mnras/article/474/2/1955/4598003 © 2017 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society OXFORD UNIV PRESS |
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en |
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galaxies: active galaxies: distances and redshifts quasars: emission lines |
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galaxies: active galaxies: distances and redshifts quasars: emission lines Hviding, Raphael E. Hickox, Ryan C. Hainline, Kevin N. Carroll, Christopher M. DiPompeo, Michael A. Yan, Wei Jones, Mackenzie L. Characterizing the WISE-selected heavily obscured quasar population with optical spectroscopy from the Southern African Large Telescope |
description |
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 similar to 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 mu m 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. |
author2 |
Univ Arizona, Steward Observ |
author_facet |
Univ Arizona, Steward Observ Hviding, Raphael E. Hickox, Ryan C. Hainline, Kevin N. Carroll, Christopher M. DiPompeo, Michael A. Yan, Wei Jones, Mackenzie L. |
author |
Hviding, Raphael E. Hickox, Ryan C. Hainline, Kevin N. Carroll, Christopher M. DiPompeo, Michael A. Yan, Wei Jones, Mackenzie L. |
author_sort |
Hviding, Raphael E. |
title |
Characterizing the WISE-selected heavily obscured quasar population with optical spectroscopy from the Southern African Large Telescope |
title_short |
Characterizing the WISE-selected heavily obscured quasar population with optical spectroscopy from the Southern African Large Telescope |
title_full |
Characterizing the WISE-selected heavily obscured quasar population with optical spectroscopy from the Southern African Large Telescope |
title_fullStr |
Characterizing the WISE-selected heavily obscured quasar population with optical spectroscopy from the Southern African Large Telescope |
title_full_unstemmed |
Characterizing the WISE-selected heavily obscured quasar population with optical spectroscopy from the Southern African Large Telescope |
title_sort |
characterizing the wise-selected heavily obscured quasar population with optical spectroscopy from the southern african large telescope |
publisher |
OXFORD UNIV PRESS |
publishDate |
2018 |
url |
http://hdl.handle.net/10150/627140 http://arizona.openrepository.com/arizona/handle/10150/627140 |
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