[en] The E.S.A. COS-B satellite performed a one-month observation pointing in the direction of M42 in Orion, during July-August 1978. An excess of high energy (above 100 MeV) photons is seen in the data, well coinciding with the Orion cloud complex. Features of such an excess are discussed, such as flux value, spectral shape and possible spatial extension of the emission. Brief astrophysical implications are then derived for the physical association of the excess with the Nebula. (author)

[en] A report on an exploratory, unbiased mapping of five COS-B high energy gamma ray sources (2CG121+04, 2CG135+01, 2CG195+04, 2CG218-00, 2CG284-00) chosen to be in regions of the Galaxy as uncrowded as possible and easily accessible by the Einstein Observatory. COS-B error boxes in the soft X-ray range are shown. Possible counterparts for the gamma ray excesses are proposed for some of the sources. (U.K.)

[en] Optical data taken in January 1987 from La Silla, compared to the discovery plate of 1975.2, show no proper motion for PSR 0833-45, while a very significant one was expected if the pulsar originated in the center of the Vela SNR, believed associated with it. The data yield a good estimate of the position of the parent SN event, highly asymmetric with respect to the present SNR and incompatible with all the Vela centers considered so far at various wavelengths. If the PSR/SNR association is to be kept, either an extreme asymmetry of the SNR is required, or both objects have to be much older than thought so far. Both alternatives are unattractive, thus casting doubts on the reality of this classic SNR/pulsar association. 25 references

[en] Optical data taken in Jan 87 from La Silla compared with the discovery plate of 1975.2 show no proper motion for PSR 0833-45 while a very significant one was expected if the pulsar originated in the center of the Vela SNR which had so far been associated with it. Data yield a good estimate of the position of the parent SN event, highly assymetric with respect to the present SNR and incompatible with all the Vela ''centers'' considered so far at various wavelengths. If the PSR/SNR association is to be maintained there must either be an extreme asymmetry of the SNR or both objects are much older than has been believed so far. Both alternatives, however, doubts on the reality of this classic SNR/pulsar association. (author). 2 figs., 27 refs

[en] Dedicated X-ray, optical, and radio observations aimed at the identification of the bright gamma-ray source 2CG195 + 04 (Geminga) are presented. A very promising candidate is found and its properties are discussed in the context of possible astrophysical scenarios. 25 references

[en] Two identifications of COS-B γ-ray excesses with known molecular clouds have already been reported: rho Oph. and Orion. Here we summarize the results obtained in (1981) and draw attention to longitudes l>240⁰ where new H1 data have become available

[en] A review of the rather optimistic predictions made in the past concerning the emission of gamma-rays from supernovae is presented. New confirmation is offered here for the hypotheses that: 1- supernovae are the main source of cosmic rays; 2- pulsars are not the most important accelerators of cosmic rays; 3- the total cosmic ray energy exceedes the total electron energy by a factor of about 100

[en] The detection by COS-B of 25 high-energy gamma-ray sources has shown that copious gamma-ray emission is produced in numerous localised regions. Owing to the mysterious nature of those objects, time variability of gamma-ray sources cannot be excluded. Since a large part of galactic plane has been observed by COS-B more than once since its launch in August 1975, a search for long-term variable gamma-ray sources in this region of the sky is possible

[en] The use of the azimuthal distribution of planes containing e(+)/e(-) pairs from high-energy photon materialization to investigate the nature of gamma-ray sources is discussed. Analytical work done on COS B data for bright COS B sources (Vela, Crab, and Geminga) and for a reference background region is presented along with results which are indicative of a low-chance-probability anisotropy effect for Vela. The case for the Vela pulsar is studied in more detail, starting from its pulsation properties and from a polarization interpretation of the observed anisotropy. A possible physical interpretation of the results is given in the context of pulsar gamma-ray emission, and requirements for future gamma-ray telescopes derived from COS B experience are examined. 29 references

[en] An X-ray exploration of a region of the Galactic plane in Carina near l = 284 deg with the Einstein Observatory is presented, consisting of two IPC and one HRI fields. Three new X-ray sources are seen, of which one is clearly extended and can be associated with RCW 49, an H II region/emission nebula, containing a cluster of young stars. The X-ray data could be consistent with a central source of diffuse emission; however, the X-ray flux appears significantly greater than that expected for an object like RCW 49. 33 references