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Variable X-ray spectra of BL Lac objects: HEAO-1 observations of PKS 0548-322 and 2A 1219+305X-ray spectra for the BL Lac objects PKS 0548-322 and 2A 1219+305 measured with the HEAO-1 A2 detectors during pointing maneuvers on September 30, 1978 and May 31, 1978 respectively are presented. Both fit single power law components with low energy absorption. For 2A 1219+305, a thermal bremsstrahlung form gives an unacceptable fit. From a comparison with other statistically poorer observations taken at 6 month intervals while the satellite was in its normal scanning mode, it is found that the sources exhibit spectral variability. A summary of measurements of the 5 BL Lac objects detected with the A2 experiment is presented and it is concluded that X-ray spectral changes in this class of source are common. Their general X-ray spectral characteristics distinguish BL Lac objects from other classes of X-ray emitting active galactic nuclei. Analysis of their total spectra indicates that most of the energy is emitted in the 5 to 100 eV band.
Document ID
19800022778
Acquisition Source
Legacy CDMS
Document Type
Preprint (Draft being sent to journal)
Authors
Worrall, D. M. (California Univ. San Diego, United States)
Boldt, E. A. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Holt, S. S. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Mushotzky, R. F. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Serlemitsos, P. J. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
September 4, 2013
Publication Date
May 1, 1980
Subject Category
Astronomy
Report/Patent Number
NASA-TM-80700
Accession Number
80N31283
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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