Detailed characteristics of the high-energy gamma radiation from PSR 0833-45 measured by COS-B.
Bignami, G. F.; Hermsen, W.; Masnou, J. L.; D'Amico, N.; Bennett, K.; Buccheri, R.; Kanbach, G.; Lichti, G. G.; Paul, J. A.; Swanenburg, B. N.; Wills, R. D.; Sacco, B.; Caraveo, P.; Mayer-Hasselwander, H. H.
Germany, Netherlands, Italy, France
Abstract
A series of COS-B observations of the high-energy gamma-ray emission from PSR 0833-45 has been combined to derive detailed temporal and spectral characteristics of this source. The gamma-ray period of the pulsar was determined for the observations spanning the time interval October 1975 to June 1977. The variation of the period with time can be expressed as a second-order polynomial including a second derivative or as an exponential function describing the post-glitch behavior of the pulsar. The spectrum of PSR 0833-45 can be represented by a power law of index 1.89 plus or minus 0.06 in the energy range 50 MeV to 3 GeV, but indications of a spectral flattening at low energies and a steepening above a few hundred MeV exist. The pulsed components emitted at different pulsar phases show marked spectral differences. No evidence of a steady gamma-ray emission from the direction of PSR 0833-45 was found.