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ROSAT and ASCA Observations of the Seyfert Galaxy 1H0419-577, Identified with LB 1727We discuss the properties of the Seyfert 1.5 galaxy LB 1727 based upon the analysis of two ASCA observations, a two-month Rosat monitoring campaign, and optical data. The target is identified with the HEAO-A1 source 1H0419-577, so it has been observed by ASCA and ROSAT in order to obtain better X-ray variability and spectra data. Only modest (20%) variability is observed within or between ASCA and BeppoSAX observations in the approximately 2 - 10 keV band. However, the soft X-ray flux increased by a factor of 3 over a period of 2 months, while it was monitored daily by the ROSAT HRI instrument. The hard X-ray continuum can be parameterized as a power-law of slope Gamma approximately 1.5 - 1.6 across 9.7 - 11 keV in the rest-frame. We also report the first detection of an iron K(alpha) line in this source, consistent with emission from neutral material. The X-ray spectrum steepens sharply below 0.7 keV yielding a power-law of slope Gamma approximately 3.2. There is no evidence for absorption by neutral material, instrinsic to the nucleus. If the nucleus is unattenuated, then the break energy between the soft-excess and hard component is 0.7+/-0.08 keV. An ionized absorber may produce some tum-up in the spectrum at low energies, but a steepening of the underlying continuum is also required to explain the simultaneous ASCA and HRI data. We cannot rule out the possibility that a significant column of ionized material exists in the line-of-sight, if that is true, then the continuum break-energy can only be constrained to lie within the approximately 0.1 - -0.7 keV band.
Document ID
19990004111
Acquisition Source
Goddard Space Flight Center
Document Type
Contractor Report (CR)
Authors
Turner, T. J.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
George, I. M.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Nandra, K.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Grupe, D.
(Eureka Scientific, Inc. Oakland, CA United States)
Remillard, R.
(Eureka Scientific, Inc. Oakland, CA United States)
Leighly, K.
(Eureka Scientific, Inc. Oakland, CA United States)
Marshall, H. L.
(Eureka Scientific, Inc. Oakland, CA United States)
Date Acquired
September 6, 2013
Publication Date
May 1, 1998
Subject Category
Astronomy
Report/Patent Number
NASA/CR-1998-208595
NAS 1.26:208595
Report Number: NASA/CR-1998-208595
Report Number: NAS 1.26:208595
Funding Number(s)
CONTRACT_GRANT: NASA Order S-57786-Z
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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