Accession Number:

ADA464511

Title:

OSSE Observations of Blazars

Descriptive Note:

Corporate Author:

GEORGE MASON UNIV FAIRFAX VA

Report Date:

1994-01-01

Pagination or Media Count:

6.0

Abstract:

The Oriented Scintillation Spectrometer Experiment OSSE on the Compton Gamma Ray Observatory has observed four of the active galactic nuclei detected by EGRET Fichtel et at. 1993 at photon energies above 100 MeV namely, 3C 273, 3C 279, MRK 421 and PKS 0528134. These sources show blazar properties at other wavelengths. Only 3C 273 and 3C 279 were detected with high significance in the OSSE energy range, 0.05 - 10 MeV. However, not all of the OSSE observations were contemporaneous with the EGRET detections. The OSSE exposures varied from 10 weeks on 3C 273 in 8 separate viewing periods to 3 weeks on PKS 052834. When combined with contemporaneous COMPTEL observations of these sources, we find strong evidence for spectral softening between the hard X-ray and medium energy gamma-ray bands in 3 of the 4 sources. Constraints provided by the OSSE observations on models of blazar emissions are discussed.

Subject Categories:

  • Optics
  • Astronomy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE