Open AccessINTEGRALandRXTEObservations of Centaurus A
Author(s) -
R. E. Rothschild,
J. Wilms,
John A. Tomsick,
R. Staubert,
S. Benlloch,
W. Collmar,
G. Madejski,
S. Deluit,
H. Khandrika
Publication year - 2006
Publication title -
the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.1086/500534
Subject(s) - physics , astrophysics , flux (metallurgy) , line of sight , centaurus a , accretion disc , power law , accretion (finance) , astronomy , limiting , galaxy , active galactic nucleus , statistics , materials science , mathematics , metallurgy , mechanical engineering , engineering
INTEGRAL and RXTE performed three simultaneous observations of the nearbyradio galaxy Cen A in 2003 March, 2004 January, and 2004 February with thegoals of investigating the geometry and emission processes via thespectral/temporal variability of the X-ray/low energy gamma ray flux, andintercalibration of the INTEGRAL instruments with respect to those on RXTE.When combined with earlier archival RXTE results, we find the power lawcontinuum flux and the line-of-sight column depth varied independently, and theiron line flux was essentially unchanging. Taking X-ray spectral measurementsfrom satellite missions since 1970 into account, we discover a variability inthe column depth between 1.0x10^23 cm^-2 and 1.5x10^23 cm^-2, and suggest thatvariations in the edge of a warped accretion disk viewed nearly edge-on mightbe the cause.Comment: 48 pages, 14 figures, 10 tables, accepted for publication by The Astrophysical Journa
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