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Quasar x-ray spectra revisitedA sample of 45 quasars observed by the Imaging Proportional Counter (IPC) on the Einstein satellite is used to re-examine the relationship between the soft (0.2-3.5 keV) X-ray energy index and radio-loudness. We found the following: (1) the tendency for radio-loud quasars to have systematically flatter X-ray slopes than radio-quiet quasars (RQQ's) is confirmed with the soft X-ray excess having negligible effect; (2) there is a tendency for the flatness of the X-ray slope to correlate with radio core-dominance for radio-loud quasars, suggesting that a component of the X-ray emission is relativistically beamed; (3) for the RQQ's the soft X-ray slopes, with a mean of approximately 1.0, are consistent with the slopes found at higher energies (2-10 keV) although steeper than those observed for Seyfert 1 galaxies (also 2-10 keV) where the reflection model gives a good fit to the data; (4) the correlation of FeII emission line strength with X-ray energy index is confirmed for radio-quiet quasars using a subset of 18 quasars. The radio-loud quasars show no evidence for a correlation. This relation suggests a connection between the ionizing continuum and the line emission from the broad emission line region (BELR) of radio-quiet quasars, but in the opposite sense to that predicted by current photoionization models; and (5) the correlations of X-ray slope with radio core dominance and FeII equivalent width within the radio-loud and radio-quiet sub-classes respectively imply that the observed wide range of X-ray spectral slopes is real rather than due to the large measuring uncertainties for individual objects.
Document ID
19930005571
Acquisition Source
Legacy CDMS
Document Type
Preprint (Draft being sent to journal)
Authors
Shastri, P.
(Texas Univ. Austin, TX, United States)
Wilkes, B. J.
(Smithsonian Astrophysical Observatory Cambridge, MA., United States)
Elvis, M.
(Smithsonian Astrophysical Observatory Cambridge, MA., United States)
Mcdowell, J.
(Smithsonian Astrophysical Observatory Cambridge, MA., United States)
Date Acquired
September 6, 2013
Publication Date
August 1, 1992
Publication Information
Publication: Smithsonian Astrophysical Observatory, The Evolution of the Quasar Continuum
Subject Category
Astronomy
Accession Number
93N14760
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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