Studies of BL Lacertae objects with the Einstein Observatory - the soft X-ray spectra of OJ 287 and PKS 0735+178

Journal Article · Fri Jul 01 04:00:00 EDT 1988 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/166511· OSTI ID:6725535

Madejski, G M; Schwartz, D A

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), Journal Name: Astrophys. J.; (United States) Vol. 330; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BASIC INTERACTIONS
BL LACERTAE OBJECTS
BREMSSTRAHLUNG
COMPTON EFFECT
COSMIC RADIO SOURCES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ELASTIC SCATTERING
ELECTROMAGNETIC INTERACTIONS
ELECTROMAGNETIC RADIATION
INTERACTIONS
IONIZING RADIATIONS
MEASURING INSTRUMENTS
PROPORTIONAL COUNTERS
RADIATION DETECTORS
RADIATIONS
SCATTERING
SOFT X RADIATION
SPECTRA
SYNCHROTRON RADIATION
VARIATIONS
X RADIATION
X-RAY SPECTRA