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Properties of X-ray-selected broad absorption-line quasars

Blustin, A. J. and Dwelly, T. and Page, M. J. and McHardy, I. M. and Seymour, N. and Kennea, J. A. and Loaring, N. S. and Mason, K. O. and Sekiguchi, K. (2008) Properties of X-ray-selected broad absorption-line quasars. Monthly Notices of the Royal Astronomical Society, 390 (3). pp. 1229-1240. ISSN 0035-8711.

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Broad absorption-line quasars (commonly termed BALQSOs) contain the most dramatic examples of active galactic nucleus (AGN) driven winds. The high absorbing columns in these winds, ~10^24 cm^-2, ensure that BALQSOs are generally X-ray faint. This high X-ray absorption means that almost all BALQSOs have been discovered through optical surveys, and so what little we know about their X-ray properties is derived from very bright optically selected sources. A small number of X-ray-selected BALQSOs (XBALQSOs) have, however, recently been found in deep X-ray survey fields. In this paper we investigate the X-ray and rest-frame ultraviolet (UV) properties of five XBALQSOs for which we have obtained XMM-Newton EPIC X-ray spectra and deep optical imaging and spectroscopy. We find that, although the XBALQSOs have an αox steeper by ~0.5 than normal QSOs, their median αox is nevertheless flatter by 0.30 than that of a comparable sample of optically selected BALQSOs (OBALQSOs). We rule out the possibility that the higher X-ray to optical flux ratio is due to intrinsic optical extinction. We find that the amount of X-ray and UV absorption due to the wind in XBALQSOs is similar, or perhaps greater than, the corresponding wind absorption in OBALQSOs, so the flatter αox cannot be a result of weaker wind absorption. We conclude that these XBALQSOs have intrinsically higher X-ray to optical flux ratios than the OBALQSO sample with which we compare them.

Item Type:Article
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Page, M. J.0000-0002-6689-6271
Seymour, N.0000-0003-3506-5536
Kennea, J. A.0000-0002-6745-4790
Additional Information:© 2008 The Authors. Journal compilation © 2008 RAS. Accepted 2008 August 11. Received 2008 August 8; in original form 2008 June 18. We wish to thank the anonymous referee for comments which improved the clarity of the paper. AJB acknowledges the support of an STFC Postdoctoral Fellowship. XMM–Newton is an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. The Subaru Telescope is operated by the National Astronomical Observatory of Japan. The W. M. Keck Observatory is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The William Herschel Telescope is operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. The Hale Telescope, Palomar Observatory, is part of a collaborative agreement between the California Institute of Technology, its divisions Caltech Optical Observatories and the Jet Propulsion Laboratory (operated for NASA), and Cornell University. The 2MASSis a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. The NASA/IPAC Infrared Science Archive is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Subject Keywords:quasars: absorption lines; quasars: individual: CXOU J014546.9-043031; quasars: individual: CXOU J014517.1-042503; quasars: individual: CXOU J014553.9-043726; quasars: individual: CXOU J014546.5-042450; quasars: individual: CXOCDFS J033209.5-274807; ultraviolet: galaxies
Issue or Number:3
Record Number:CaltechAUTHORS:BLUmnras08
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13322
Deposited By: Tony Diaz
Deposited On:16 Apr 2009 20:08
Last Modified:02 Dec 2019 21:38

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