Studies of BL Lacertae objects with the Einstein Observatory - the soft X-ray spectra of OJ 287 and PKS 0735+178
Accurate, soft X-ray spectra of two BL Lac objects, OJ 287 and PKS 0735+178, are presented. The X-ray spectra are well described by a power-law model with a low-energy cutoff consistent with photoelectric absorption within the Galaxy. The best-fit values of the energy spectral index in the 0.2-4.0 keV band are 0.91 and 0.76 respectively. The X-ray flux from OJ 287 is variable by a ratio of three from low to high state; PKS 0735+178 shows no indication of X-ray variability. The X-ray emission in OJ 287 is interpreted to be due to the synchrotron process from a volume common with either a beamed radio component or a stationary optical component. In PKS 0735+178, where the X-ray emission is most likely due to the Compton process operating in one of the VLBI radio components. The synchrotron self-Compton process with modest kinematic Doppler factors predicts the measured X-ray flux from PKS 0735+178 and lower than the measured flux in OJ 287. 64 references.
- Research Organization:
- NASA, Goddard Space Flight Center, Greenbelt, MD (USA); Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (USA)
- OSTI ID:
- 6725535
- Journal Information:
- Astrophys. J.; (United States), Vol. 330
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
BL LACERTAE OBJECTS
X-RAY SPECTRA
COMPTON EFFECT
COSMIC X-RAY SOURCES
PROPORTIONAL COUNTERS
SOFT X RADIATION
SYNCHROTRON RADIATION
VARIATIONS
BASIC INTERACTIONS
BREMSSTRAHLUNG
COSMIC RADIO SOURCES
COSMIC RAY SOURCES
ELASTIC SCATTERING
ELECTROMAGNETIC INTERACTIONS
ELECTROMAGNETIC RADIATION
INTERACTIONS
IONIZING RADIATIONS
MEASURING INSTRUMENTS
RADIATION DETECTORS
RADIATIONS
SCATTERING
SPECTRA
X RADIATION
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources