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Analysis of the COS B Data for Evidence of Linear Polarization of VELA Pulsar Gamma Rays
Mattox, John R.; Mayer-Hasselwander, Hans A.; Strong, Andy W.
The COS B spark chamber telescope observations of the Vela pulsar were analyzed for gamma-ray polarization. No significant quadrupole moment is found in the azimuthal distribution of the electron-positron pair production planes. However, analysis of the sensitivity indicates that even 100-percent polarization would not be detected. Therefore, the …
A New Powerful Test for Periodic Pulsed Emission of High-Energy Photons
Swanepoel, J. W. H.; de Beer, C. F.
A novel stastistical test devised for detecting periodic pulsations in a series of photon arrival times is found to perform powerfully in the detection of multiple, narrow peaked light curve shapes against a uniform background, especially if the light curve has multiple peaks. The statistical test has been applied to observations of the first 1350…
CO Observations of the Cepheus Flare. II. Gamma Rays from the Interstellar Gas and a Possible New COS B Source
Grenier, I. A.; Lebrun, F.
The correlation between the distribution of the interstellar gas in the Cepheus Flare region (100^deg^ <= l <= 141^deg^, 8^deg^ <= b <= 22^deg^) and that of the diffuse gamma radiation originating in these nearby clouds has been studied in detail. A maximum-likelihood analysis has been applied to compare maps of the atomic and molecula…
COS-B: The highlights
Bennett, Kevin
The COS-B satellite operated from August 1975 until April 1982 during which time an extensive survey of the Galaxy was made in the energy range 50 MeV to 5 Gev. The Caravane Collaboration built the gamma-ray telescope and performed the bulk of the scientific data reduction. Since the data are now available to the Astrophysics community at large, s…
Galactic gamma — ray sources in the 40-50 MeV range
Li, Ti-Pei; Wu, Mei
A gamma-ray map of the Galaxy in 40-50 MeV reveals, besides the three sources known at higher energies, four additional sources with intensities comparable to that of the Crab.
PSR 1820-11: a binary gamma-ray pulsar.
Li, Ti-Pei; Wu, Mei
Significant pulsation structure in the phase distribution of 50 - 6000 MeV gamma-rays from the direction of the binary radio pulsar PSR 1820-11 in the COS-B data was obtained by the folding algorithm. Besides period searches, a spatial analysis was performed and a clear point-like image at the pulsar's position for gamma-rays above 50 MeV was obta…
Pulsed gamma-rays from PSR 1951 + 32
Li, Ti-Pei; Wu, Mei; Ma, Yu-Qian +1 more
In a previous paper [1] we obtained statistically significant evidence for a 39-ms period in the COS-B data of 30-5000 MeV gamma rays in the direction of PSR 1951 + 32. Most of the gamma photons from PSR 1951 + 32 are pulsed and concentrated in a narrow interval of phase. We have examined the partical distribution of gamma ray intensity in the reg…
Searches in the COS-B Gamma Ray Data-Base for Pulsations from PSR 1951+32
D'Amico, N.; Bennett, K.; Buccheri, R. +3 more
TeV and MeV gamma-rays from binary systems
Carollo, C. M.; Raubenheimer, B. C.; Buccheri, R. +4 more
We report the third consecutive detection of Vela X-1 as a source of VHE gamma-rays ( Eγ > 1 TeV) with a 99.92 % significance. The pulsed emission shows a broad sinusoidal light curve at a period similar to the X-ray value, with a large negative period derivative over the 60 days of observation. We also report our observations on Cen…
PSR 1820-11 : A binary gamma-ray pulsar
Wu, Mei; Li, Ti-pei
Significant pulsation structure in phase distribution in the 50-6000MeV gamma-rays from the direction of the binary radio pulsar PSR 1820-11 in the COS-B data was obtained using the folding algorithm. Besides the period search, a spatial analysis was Bade and a clear point-like gamma-ray image was found at the pulsar's position.