X-Ray Observations of the BL Lacertae Object OJ 287 with ASCA
Abstract
Reports have been made on the X-ray properties of the BL Lacertae object OJ 287, obtained with ASCA on 1994 November 18--19. Although the observation was made during a period of enhanced optical intensity, the obtained 0.5--10 keV flux falls below those from previous X-ray observations. Intensity variations on time scales of a few hours were detected, with a typical peak-to-peak amplitude of 20%. The X-ray spectra acquired with the SIS and the GIS are described consistently with a single power-law model with the galactic absorption, and the required photon index, ~ 1.7, is flatter than most of those previously observed from this object. The derived monochromatic X-ray flux at 1 keV, 0.76 mu Jy, exceeds the extrapolation from the lower frequency continua, which is based on near-simultaneous multi-band observations. A discussion is made concerning the origin of X-ray emission from OJ 287 in terms of the synchrotron and synchrotron-self-Compton mechanisms.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- December 1997
- DOI:
- 10.1093/pasj/49.6.631
- Bibcode:
- 1997PASJ...49..631I
- Keywords:
-
- BL LACERTAE OBJECTS;
- GALAXIES: INDIVIDUAL (OJ 287);
- X-RAYS: SPECTRA