Search Publications
The gamma-ray deficit toward the Galactic Center.
Hermsen, W.; Bloemen, J. B. G. M.; Blitz, L. +1 more
The gamma-ray flux (E greater than 300 MeV) from the central few hundred parsecs of the Milky Way is shown to be nearly an order of magnitude smaller than the value expected from the H2 masses generally estimated to be present in the center and from the average gamma-ray emissivity measured for the disk. This result implies that in the Galactic ce…
COS-B gamma-ray sources and interstellar gas in the first galactic quadrant. Caravane collaboration for the COS-B satellite.
Caraveo, P. A.; Bignami, G. F.; Strong, A. W. +8 more
The consequences are considered for the high-energy gamma-ray sources of the recently established correlation between the intensity above 300 MeV, and tracers of atomic and molecular gas, in the first quadrant of the Galaxy. Using a likelihood method on the complete set of COS-B data, it is shown that there are point-like gamma-ray sources which d…
The interstellar radiation field and the production of inverse-Compton gamma rays in the Galaxy
Bloemen, J. B. G. M.
An empirical model for the large-scale galactic distribution of the various components of the interstellar radiation field is constructed using recent observations, and the spectral and spatial distribution of inverse Compton (IC) gamma ray production in the Galaxy is determined using the most recent estimate of the interstellar electron spectrum …
The galactic gamma-ray distribution - Implications for galactic structure and the radial cosmic-ray gradient
Harding, A. K.; Stecker, F. W.
The radial distribution of gamma ray emissivity in the Galaxy was derived from flux longitude profiles, using both the final SAS-2 results and the recently corrected COS-B results and analyzing the northern and southern galactic regions separately. The recent CO surveys of the Southern Hemisphere were used in conjunction with the Northern Hemisphe…
Gamma-ray emission from atomic and molecular gas at intermediate galactic latitudes
Strong, A. W.
Recent developments in the study of the correlations between gamma-rays and local gas tracers are described. COS-B data in the range between b of 10 and 20 deg are analyzed using simultaneous 21-cm and galaxy count data, in order to separate the roles of atomic and molecular gas. The new galaxy-count calibration of Strong (1983) is used, and the r…
Multicomponent Analysis of Total Cos-B Gamma-Ray Data at Intermediate Latitudes
Strong, A. W.; Mayer-Hasselwander, H. A.; Bloemen, J. B. G. M. +1 more
The final COS-B database has been used to study the gamma-ray emission in the latitude range 10° < |b| < 20° in terms of a four component model. The emissivity spectrum of the local interstellar medium is derived and compared with that found in previous studies. The intensity of the inverse-Compton component is determined from the fitting pr…
The final COS-B database now publicly available
Caraveo, P. A.; Bignami, G. F.; Hermsen, W. +7 more
The data obtained by the gamma-ray satellite COS-B have been processed, condensed and integrated together with the relevant mission and experiment parameters into the "Final COS-B Database". The database contents and the access programs available with the database are outlined. The final sky coverage and a presentation of the large-scale distribut…
Cos-B Gamma-Ray Sources and Interstellar Gas
Caraveo, P. A.; Bignami, G. F.; Strong, A. W. +8 more
Of the gamma-radiation observed above 100 MeV only a few percent is due to the catalogued sources which are viewed against intense background mission from the Galactic plane. There has been considerable recent success in modelling the Galactic plane emission as the interactions of cosmic rays with atomic and molecular interstellar gas; Bloemen, et…
Cygnus X-3 not Seen at High-Energy Gamma-Rays
Hermsen, W.
The ESA satellite COS-B viewed the Cyg-X region 7 times between November 1975 and March 1982. A search for periodic gamma-ray emission (E > 70 MeV) from Cyg X-3 at the characteristic ∼4.8 h period did not reveal the source. Combining all observations, the 2σ upperlimit (E > 70 MeV) on the flux for the phase interval in which X-ray emission h…
CYG X-3: not Seen in High-Energy Gamma Rays by Cos-B
Caraveo, P. A.; Bignami, G. F.; Strong, A. W. +7 more
COS-B had Cyg X-3 within its field of view during 7 observation periods between 1975 and 1982 for in total approximately 300 days. In the skymaps (70 meV E 5000 meV) of the Cyg-X region produced for each of these observations and in the summed map, a broad complex structure is visible in the region 72 deg approximately less than 1 approximately le…