1996A&AS..120C.549S -
Astron. Astrophys., Suppl. Ser., 120C, 549-552 (1996/December-3)
First Cycle 4 multiwavelength observations of the gamma-ray quasar PKS 0208-512.
STACY J.G., VESTRAND W.T., SREEKUMAR P., BONNELL J., KUBO H. and HARTMAN R.C.
Abstract (from CDS):
We present first results of CGRO Cycle 4 multiwavelength observations of the gamma-ray quasar PKS 0208-512. A bright, variable gamma-ray source, PKS 0208-512 has been detected numerous times by the EGRET experiment aboard the CGRO, possessing one of the hardest spectra observed to date. The recent COMPTEL observations of Blom et al. (
1995A&A...298L..33B) indicate that PKS 0208-512 may belong to a new class of AGN that flare at MeV energies. During the current CGRO Cycle 4 observing cycle we have obtained observations of PKS 0208-512 at high- and medium-energy gamma-rays with the EGRET and COMPTEL instruments aboard the Compton Observatory, at X-ray energies with ASCA, and at ultraviolet wavelengths with IUE. Preliminary analysis of our first CGRO Cycle 4 multiwavelength observations of 208 indicates a significant softening in the high-energy gamma-ray spectrum of this source, compared to earlier epochs. A possible correlation is also noted in flux variations between simultaneous ultraviolet (IUE) and X-ray (ASCA) measurements of this source. Our multiwavelength observations of 208 will be greatly expanded during the CGRO Cycle 5 in 1996, and our results on 0208-512 will ultimately be included in a larger survey of the gamma-ray properties of flat-spectrum radio quasars toward the region of the South Galactic Pole (see Vestrand et al.,
1996A&AS..120C.521V).
Abstract Copyright:
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Journal keyword(s):
gamma rays: observations - galaxies: active - quasars: individual: PKS 0208-512
CDS comments:
Special Issue "3rd Compton Symposium"
Simbad objects:
2
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