EGRET/COMPTEL Observations of an Unusual, Steep-Spectrum Gamma-Ray Source

D. J. Thompson, D.L. Bertsch, R.C. Hartman

W. Collmar


During analysis of sources below the threshold of the third EGRET catalog, we have discovered a source, named GRO J1400-3956 based on the best position, with a remarkably steep spectrum. Archival analysis of COMPTEL data shows that the spectrum must have a strong turn-over in the energy range between COMPTEL and EGRET. The EGRET data show some evidence of time variability, suggesting an AGN, but the spectral change of slope is larger than that seen for most gamma-ray blazars. The sharp cutoff resembles the high-energy spectral breaks seen in some gamma-ray pulsars. There have as yet been no OSSE observations of this source.

File translated from TEX by TTH, version 2.32.
On 16 Jul 1999, 09:19.