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Evidence for Gamma-Ray Flares in 3C 279 and PKS 1622-297 at ~10 MeV

W. Collmar·V. Schoenfelder·H. Bloemen·J. J. Blom·W. Hermsen·M. McConnell·J. G. Stacy·K. Bennett·O. R. Williams
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Abstract

The EGRET experiment aboard the Compton Gamma-Ray Observatory (CGRO) has observed at energies above 100 MeV strong gamma-ray flares with short-term time variability from the gamma-ray blazars 3C 279 and PKS 1622-297. During these flaring periods both blazars have been detected by the COMPTEL experiment aboard CGRO at photon energies of about 10 MeV, revealing simultaneous gamma-ray activity down to these energies. For both cases the derived fluxes exceed those measured in previous observations, and 3C 279 shows an indication for time variability within the observational period. Both sources show evidence for `hard' MeV spectra. In general the behaviour of both sources at gamma-ray energies is found to be quite similar supporting the conclusion that the underlying physical mechanism for both gamma-ray flares might be the same.

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W. Collmar, V. Schoenfelder, H. Bloemen, J. J. Blom, W. Hermsen, M. McConnell, J. G. Stacy, K. Bennett, O. R. Williams. 1997-11-11. Evidence for Gamma-Ray Flares in 3C 279 and PKS 1622-297 at ~10 MeV. https://doi.org/10.1063/1.54054

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