Simultaneous Radio and X-Ray Observations of Active Extragalactic Objects During the ROSAT All Sky Survey.
Abstract
During the 6-month all sky survey by ROSAT, selected AGNs near the ecliptic pole were monitored intensively at centimeter wavelengths in total flux density and linear polarization. We present X-ray and radio results from this study for twelve sources which had ROSAT windows of 6 to 29 days. All were observed with the University of Michigan 26-meter telescope at 4.8, 8.0 and 14.5 GHz, and six were also observed with the VLA at 15 GHz. The ROSAT observing window for one source, 1739+522, occurred during the rise portion of a large radio outburst. X-ray emission was detected in 10 of the sources, but all were relatively weak (typically only a few X-ray photons per orbit). No short-term X-ray variations were found for any of these sources, but, because of the source strengths, we can only exclude large amplitude (>=50%) variations. X-ray variations have previously been reported in an additional AGN, 3C 371, that we monitored during its ROSAT window, (Fink et al. private communication), but we find no large amplitude radio variations in this source. Time averaged X-ray and radio fluxes and spectral indices are presented, and these data are compared with SSC model predictions to place limits on the physical parameters of the emitting regions in these objects. We thank S. Schaeidt for preparing the ROSAT light curve computer program and the ROSAT team for preparing the survey data. This work was supported in part by NASA grant NAG5-1820 and by NSF grant AST-8815678. The VLA of the NRAO is operated by Associated Universities Inc., under a cooperative agreement with the NSF.
- Publication:
-
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 1992
- Bibcode:
- 1992AAS...181.3504A