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X-Raying the Ultraluminous Infrared Starburst Galaxy and Broad Absorption Line QSO Markarian 231 with ChandraWith 40 ks of Clzandra ACIS-S3 exposure, new information on both the starburst and QSO components of the X-ray emission of Markarian 231, an ultraluminous infrared galaxy and broad absorption line QSO, has been obtained. The bulk of the X-ray luminosity is emitted from an unresolved nuclear point source, and the spectrum is remarkably hard, with the majority of the flux emitted above 2 keV. Most notably, significant nuclear variability (a decrease of -45% in approximately 6 hr) at energies above 2 keV indicates that Chuizdra has probed within light-hours of the central black hole. Although we concur with Maloney & Reynolds that the direct continuum is not observed, this variability coupled with the 188 eV upper limit on the equivalent width of the Fe K o emission line argues against the reflection-dominated model put forth by these authors based on their ASCA data. Instead, we favor a model in which a small, Compton-thick absorber blocks the direct X-rays, and only indirect, scattered X-rays from multiple lines of sight can reach the observer. Extended soft, thermal emission encompasses the optical extent of the galaxy and exhibits resolved structure. An off-nuclear X-ray source with a 0.35-8.0 keV luminosity of Lx = 7 x 10 sup39 ergs s sup -1 , consistent with the ultraluminous X-ray sources in other nearby starbursts, is detected. We also present an unpublished Faint Object Spectrograph spectrum from the Hirhhle Spuce Telescope archive showing the broad C IV absorption.
Document ID
20040139897
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Gallagher, S. C.
(Pennsylvania State Univ. University Park, PA, United States)
Brandt, W. N.
(Pennsylvania State Univ. University Park, PA, United States)
Chartas, G.
(Pennsylvania State Univ. University Park, PA, United States)
Garmire, G. P.
(Pennsylvania State Univ. University Park, PA, United States)
Sambruna, R. M.
(George Mason Univ. Fairfax, VA, United States)
Date Acquired
August 22, 2013
Publication Date
April 20, 2002
Publication Information
Publication: The Astrophysical Journal
Publisher: Chicago Univ. Press
Volume: 569
Issue: 2 Pt 1
ISSN: 0004-637X
Subject Category
Astronomy
Funding Number(s)
CONTRACT_GRANT: NAS8-38252
CONTRACT_GRANT: NAG5-8107
CONTRACT_GRANT: NGT5-50277
Distribution Limits
Public
Copyright
Other

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