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Title: THE LONG-TERM X-RAY VARIABILITY OF BROAD ABSORPTION LINE QUASARS

Abstract

We analyze the long-term (rest-frame 3-30 yr) X-ray variability of 11 broad absorption line (BAL) quasars, mainly to constrain the variation properties of the X-ray absorbing shielding gas that is thought to play a critical role in BAL wind launching. Our BAL quasar sample has coverage with multiple X-ray observatories including Chandra, XMM-Newton, BeppoSAX, ASCA, ROSAT, and Einstein; 3-11 observations are available for each source. For seven of the eleven sources we have obtained and analyzed new Chandra observations suitable for searching for any strong X-ray variability. We find highly significant X-ray variability in three sources (PG 1001+054, PG 1004+130, and PG 2112+059). The maximum observed amplitude of the 2-8 keV variability is a factor of 3.8 {+-} 1.3, 1.5 {+-} 0.2, and 9.9 {+-} 2.3 for PG 1001+054, PG 1004+130, and PG 2112+059, respectively, and these sources show detectable variability on rest-frame timescales down to 5.8, 1.4, and 0.5 yr. For PG 1004+130 and PG 2112+059 we also find significant X-ray spectral variability associated with the flux variability. Considering our sample as a whole, we do not find that BAL quasars exhibit exceptional long-term X-ray variability when compared to the quasar population in general. We do not find evidencemore » for common strong changes in the shielding gas owing to physical rearrangement or accretion-disk rotation, although some changes are found; this has implications for modeling observed ultraviolet BAL variability. Finally, we report for the first time an X-ray detection of the highly polarized and well-studied BAL quasar IRAS 14026+4341 in its new Chandra observation.« less

Authors:
; ;  [1];  [2];  [3]
  1. Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)
  2. Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada)
  3. Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile)
Publication Date:
OSTI Identifier:
22086485
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 759; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; ACCRETION DISKS; AMPLITUDES; ASTROPHYSICS; COMPUTERIZED SIMULATION; COSMOLOGY; GAMMA ASTRONOMY; KEV RANGE; QUASARS; ROTATION; STELLAR WINDS; ULTRAVIOLET RADIATION; X RADIATION; X-RAY DETECTION; X-RAY GALAXIES

Citation Formats

Saez, C., Brandt, W. N., Garmire, G. P., Gallagher, S. C., and Bauer, F. E. THE LONG-TERM X-RAY VARIABILITY OF BROAD ABSORPTION LINE QUASARS. United States: N. p., 2012. Web. doi:10.1088/0004-637X/759/1/42.
Saez, C., Brandt, W. N., Garmire, G. P., Gallagher, S. C., & Bauer, F. E. THE LONG-TERM X-RAY VARIABILITY OF BROAD ABSORPTION LINE QUASARS. United States. doi:10.1088/0004-637X/759/1/42.
Saez, C., Brandt, W. N., Garmire, G. P., Gallagher, S. C., and Bauer, F. E. Thu . "THE LONG-TERM X-RAY VARIABILITY OF BROAD ABSORPTION LINE QUASARS". United States. doi:10.1088/0004-637X/759/1/42.
@article{osti_22086485,
title = {THE LONG-TERM X-RAY VARIABILITY OF BROAD ABSORPTION LINE QUASARS},
author = {Saez, C. and Brandt, W. N. and Garmire, G. P. and Gallagher, S. C. and Bauer, F. E.},
abstractNote = {We analyze the long-term (rest-frame 3-30 yr) X-ray variability of 11 broad absorption line (BAL) quasars, mainly to constrain the variation properties of the X-ray absorbing shielding gas that is thought to play a critical role in BAL wind launching. Our BAL quasar sample has coverage with multiple X-ray observatories including Chandra, XMM-Newton, BeppoSAX, ASCA, ROSAT, and Einstein; 3-11 observations are available for each source. For seven of the eleven sources we have obtained and analyzed new Chandra observations suitable for searching for any strong X-ray variability. We find highly significant X-ray variability in three sources (PG 1001+054, PG 1004+130, and PG 2112+059). The maximum observed amplitude of the 2-8 keV variability is a factor of 3.8 {+-} 1.3, 1.5 {+-} 0.2, and 9.9 {+-} 2.3 for PG 1001+054, PG 1004+130, and PG 2112+059, respectively, and these sources show detectable variability on rest-frame timescales down to 5.8, 1.4, and 0.5 yr. For PG 1004+130 and PG 2112+059 we also find significant X-ray spectral variability associated with the flux variability. Considering our sample as a whole, we do not find that BAL quasars exhibit exceptional long-term X-ray variability when compared to the quasar population in general. We do not find evidence for common strong changes in the shielding gas owing to physical rearrangement or accretion-disk rotation, although some changes are found; this has implications for modeling observed ultraviolet BAL variability. Finally, we report for the first time an X-ray detection of the highly polarized and well-studied BAL quasar IRAS 14026+4341 in its new Chandra observation.},
doi = {10.1088/0004-637X/759/1/42},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 759,
place = {United States},
year = {2012},
month = {11}
}