Search Publications
Search for pulsed γ-ray emission from radio pulsars in the COS-B data.
Caraveo, P. A.; Bignami, G. F.; Strong, A. W. +13 more
Pulsed gamma-ray emission from radio pulsars has been sought in a study of pulsar parameters for 145 radio observations, contemporary with gamma-ray observations, by the COS-B spacecraft. No signal has been detected in the 50 MeV-2 GeV energy range of the study, either globally or from individual pulsars. These results indicate that the average pr…
Gamma-rays from atomic and molecular gas in the first galactic quadrant
Caraveo, P. A.; Bignami, G. F.; Strong, A. W. +15 more
The fully sampled Columbia 1 deg CO survey and the Berkeley H I survey are compared with the COS B gamma-ray survey. As a first step, the study is limited to the high-energy gamma-rays (E greater than 300 MeV). It is found that a simple model, in which uniformly distributed cosmic rays interact with the interstellar gas, as traced by H I and CO, c…
Gamma-Ray Sources Observed by Cos-B
Hermsen, W.
The nature of the fine-scale structure in the gamma-ray distribution is not yet disclosed. Considerable debate is going on whether these structures which appear point-like in the data, are mainly diffuse in nature or are genuinely compact objects. Most of the uncertainty is due to the experimental limitations. A status report is presented on the e…
Gamma-ray observations toward NGC 1275 and the origin of the emissionin the infrared, X-rays, and gamma-rays.
Bignami, G. F.; Strong, A. W.
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 studie…
Galactic gamma radiation : the contribution from discrete sources.
Houston, B. P.; Wolfendale, A. W.
The contribution from discrete sources to the emission of galactic gamma rays is studied based on an analysis of the SAS II satellite data. The data are analyzed using cross-correlation techniques, and the results are interpreted using extensive Monte-Carlo simulations of the gamma-ray sky. These results are compared to earlier analyses based on t…
X-ray observations of bright galactic bulge sources in the vicinity of GX 5-1.
van der Klis, M.; Rappaport, S.
Results are presented for 44 d of pointed COS-B X-ray observations of the galactic center region around GX5-1. It is found that GX5-1 exhibits relatively rapid (≡103 s) intensity transitions as well as flaring events with a typical time scale of ≡104 s. Neither GX5-1, GX3+1 nor GX9+1 shows evidence of periodic intensity modul…
A method to improve the visibility of time-variable gamma-ray sources in structured background
Mayer-Hasselwander, H. A.; Oezel, M. E.
For the investigation of time variable gamma-ray sources (e.g. pulsars) embedded in a spatially structured background emission, the spatial selection of those gamma-ray events which are probable to increase the observed signal is not a trivial task. A method is presented which allows for the optimum event selection without introducing any statisti…
Search for Gamma Rays of Energies E > 10**15 EV from Discrete Sources
Samorski, M.; Stamm, W.
The data of the extensive air shower experiment at Kiel have been systematically scanned for possible gamma-ray sources in the energy range E > 1015eV and declination range δ = 25° - 75°. Photon fluxes for the six statistically most significant source candidates and 3 σ upper limit photon fluxes for COS B gamma-ray sources are presen…
Diffuse Galactic Emission of High Energy Gamma Rays
Hartman, R. C.; Fichtel, C. E.; Kniffen, D. A.
A study of the gamma-radiation produced by the interaction of cosmic rays with the interstellar matter and photons is extended, based on recent COS-B satellite results and background estimates (1982) and evaluations of the 21-cm radiation in the Galaxy. Gamma-ray intensities predicted over the latitude range of -10 to 10 degrees for energy ranges …
COS-B measurements of high-latitude gamma rays and evidence for a component not related to the gas.
Caraveo, P. A.; Bignami, G. F.; Strong, A. W. +7 more
The gamma ray latitude distribution for absolute value of b between 10 deg and 90 deg measured by COS-B is compared with the expected emission from cosmic-ray/gas interactions. An additional component is found which is unrelated to the gas, and which may be interpreted as a gamma-ray 'halo'. The possibility of an inverse-Compton origin is discusse…