Search Publications
Gamma rays from atomic and molecular gas in the large complex of clouds in Orion and Monoceros.
Caraveo, P. A.; Strong, A. W.; Hermsen, W. +4 more
COS-B gamma-ray observations of the large complex of interstellar clouds in Orion and Monoceros are compared with the Columbia CO survey and the Berkeley H I surveys of this region. A good correlation between the gamma-ray emission and the total gas distribution is found. The observed gamma-ray emission can be explained in terms of interactions of…
The radial distribution of galactic gamma rays. II - The distribution of cosmic-ray electrons and nuclei in the outer galaxy
Caraveo, P. A.; Bignami, G. F.; Strong, A. W. +7 more
In the present derivation of the radial distribution of high energy gamma-ray emissivity in the outer Milky Way, the kinematics of H I are used to construct column-density maps in various galactocentric distance ranges that are then used in combination with COS-B spacecraft gamma-ray data to determine emissivities in these distance ranges. The res…
A study of the diffuse galactic gamma radiation.
Fichtel, C. E.; Kniffen, D. A.
The observed diffuse galactic gamma radiation is compared to that predicted from galactic cosmic ray interactions with galactic matter and photons, assuming that on a broad scale the galactic cosmic rays in the plane are correlated with matter density. Recent considerations of the galactic diffuse matter distribution, particularly the molecular hy…
The orbital parameters and the X-ray pulsation of VELA X-1 (4U 0900-40).
van der Klis, M.; Bonnet-Bidaud, J. M.
Results are presented of an analysis of 83 d of 2 - 12 keV X-ray observations of Vela X-1 (4U 0900-40) obtained with the ESA COS-B satellite. Combining the present determinations of the orbital epoch from pulse timing with those obtained with other satellites, the data are found to be consistent with an increase of the orbital period at a rate (P/…
On the nature of the galactic gamma-ray sources.
Morfill, G. E.; Bignami, G.; Forman, M.
Available data constrain possible models of the gamma-ray point (or pointlike) sources found by COS B. Apart from the pulsars (Crab, Vela) and possibly the quasar 3C 273, which are "compact" objects, and which have been identified at other photon energies, there are some 20-odd other sources with no accepted or acceptable counterpart, as yet. This…
Gamma rays from accreting matter onto collapsed objects
Giovannelli, F.; Karakula, S.; Tkaczyk, W.
In the spherical accretion onto massive objects, the matter may be heated up to temperatures as high as 1012 °K. In such a hot plasma, the thermal bremsstrahlung (e-e and e-p) and π° decay from inelastic collisions of protons are the main γ-ray sources. We determined the γ -ray production spectra from the π° decay and from bremsstrahlun…
Studies of high-latitude gamma rays
Strong, A. W.
COS-B gamma-ray data (70-5000 MeV) in the latitude range 10°< b <90° are compared with the expected emission from cosmic-ray interactions with interstellar gas. An additional component is found to be necessary to explain the latitude dependence of the emission. Two possible origins for this component are discussed: a gamma-ray halo around th…
Search for discrete gamma-ray sources emitting at energies greater than 10(exp15) eV.
Samorski, M.; Stamm, W.
The data of the extensive air shower experiment at Kiel have been scanned systematically for possible discrete γ-ray sources in the energy range E > 1015 eV and in the declination band δ = 25° - 75°. Photon fluxes for celestial positions with the statistically most significant excesses of showers and 3 σ upper limit photon fluxes for…
Correlation of gamma-ray fluxes with southern hemisphere CO data.
Manchester, R. N.; Wolfendale, A. W.; Whiteoak, J. B. +3 more
A new radio survey of the C-12O molecule in the Galactic plane covering the longitude range l:294 - 358 deg is compared with the flux of high energy gamma rays in the same region. A good correlation between the two is found, and it is shown that the data are consistent with the hypothesis that most of the gamma-ray flux is produced by the cosmic-r…
Rapid short-term pulse-period variations in Vela X-1 (4U 0900-40)
van der Klis, M.; Bonnet-Bidaud, J. M.
Results are presented of an analysis of 83 days of 2-12 keV X-ray observations of Vela X-1 (4U 0900-40) obtained during three separate pointings with the ESA COS-B satellite. The pulsation period is shown to undergo very rapid intrinsic changes, at a rate of up to P˙/P ~ 10-1 yr-1 during intervals of a few days. The lower val…