Gamma-ray observations toward NGC 1275 and the origin of the emissionin the infrared, X-rays, and gamma-rays.

Abstract

The COS B gamma-ray data used in the present search for possible emission mechanisms in the halo and nucleus of NGC 1275 show a gamma-ray excess at the galaxy's position which, if interpreted as emission from the galaxy, yields consequences concerning the origin of the hard X-rays and the IR-optical emission from the nucleus. These data are studied in the context of various synchrotron self-Compton (SSC) models for the nucleus. If the nonthermal spectrum includes the observed 10-micron region, the SSC process can easily produce the observed X- and gamma-ray fluxes. If SSC only extends to X-ray energies, the same electrons can produce the gamma-rays by inverse-Compton on the IR and optical radiation fields (if these originate in the nucleus).