[en] Massive stars interact with their parent molecular cloud by means of their ionizing flux and strong winds, thereby creating giant, hollow HII regions. To account for the observed structure of these HII regions, it appears necessary that all the wind energy be dissipated. Dorland and Montmerle have recently proposed a new dissipation mechanism, in the process, diffuse hard X-rays are emitted. If the observed galactic X-ray ''ridge'' results from this process on a galactic scale, it can be accounted for by the interaction of ∼3000 Wolf-Rayet stars (mostly within a ∼6.5 kpc ring) with their surrounding interstellar gas. This result is essentially consistent with the suggestion by Prantzos and Casse that the galactic ²⁶Al γ-ray line emission originates in Wolf-Rayet stars

[en] Progress towards understanding the nature of the COS-B galactic gamma-ray sources was made by two recent developments. The developments are: (1) the existence of extensive wide-latitude CO surveys, from the Northern Hemisphere, and from the Southern Hemisphere which give more precise information on molecular cloud population of the Perseus, Sagittarius, and Carina spiral arms; (2) the study of the time variability of gamma-ray sources in gamma-rays but also at other wavelengths, leading to the discovery of four new variable sources in addition to the already known Crab and Vela pulsars. Three classes of gamma-ray sources are found; invariable sources, active sources, and passive sources

[en] A review on the origin of cosmic rays and γ-rays in the galaxy is presented with emphasis on proton acceleration by shocks in stellar winds

No abstract available

[en] Although supernova explosions are widely thought to give rise to cosmic rays (nucleons), there is, as yet, no direct evidence from individual objects to support this view. A possible tool in this respect is the detection of γ-rays emitted by supernova remnants (SNRs) via π⁰ decay. However, the accumulating γ-ray data show that SNRs as a class are not γ-ray sources, but rather that γ-ray sources are, in general, closely linked with young objects. We examine, among other possibilities, whether a restricted class of SNRs are actually γ-ray sources; we restrict the class to those SNRs physically linked with extreme Population I objects. Spatial coincidences between SNRs and OB associations or H II regions (SNOBs) are sought by various methods, and this yields a list of about 30 objects (which is certainly incomplete). From the Cos B data, one finds that five (perhaps six) out of 11 as yet unidentified γ-ray sources (above 100 MeV) are associated with SNOBs, and there is a hint that as much as three-fourths of the best identified SNOBs are seen in γ-rays. The associated probabilities of chance coincidence are approx.10^-4. Angular and other statistical considerations also support this association. Pending confirmation, if a substantial proportion of the observed γ-rays does come from π⁰ decay, SNOBs appear to be a major source of galactic cosmic rays, in which cosmic-ray (> or =2 GeV) energy densities in the range approx.10--100 times the solar neighborhood value are found. A phenomenological scenario is suggested. Cosmic rays are produced by a two-step process, in which low-energy (MeV range) particles are injected by young stars pertaining to an OB association, and are subsequently accelerated by the shock wave of a neighboring supernova explosion. Isolated SNRs, possible links with light-element production, and the links between SNOBS and other astronomical objects are discussed

[en] The γ-ray source 2CG288-00, observed by COS-B in the direction of the Carina Nebula, can be plausibly interpreted in the framework of our idealized model, in which the cosmic rays are accelerated at the shock boundary of the stellar winds, and are partially confined in the HII region and in the molecular cloud. The cosmic-ray density near the acceleration region is high; however, the associated pressure remains low with respect to the gas pressure (this does not hold for very high-energy particles, > 100 GeV) and its effect on the shock structure is negligible

[en] Very recently, ROSAT and ASCA have been able to detect X-rays from protostars typically 10 times younger than T Tauri stars (i.e., having ages ∼ 10⁵ yrs), in spite of their heavy extinction (A_V ∼ 30 - 60). The intrinsic luminosities, either quiescent or in the form of flares, are ∼ 10 times higher than T Tauri stars or more. In one particular case (a well-documented protostar in the nearby ρ Oph cloud, YLW15), the (L_X(L_bol)) ratio has been > 1 during a 'superflare'. This high value implies not a stellar origin, but rather (for the first time) star-disk and/or star-envelope magnetic interactions, not unlike those invoked for compact objects. The present status of X-ray emission by protostars, as seen with ROSAT and ASCA, is summarized

[en] This volume gathers the invited papers presenting the selected properties of the neutrino and the quest for their detection, the most recent results obtained in their research and some of its astrophysical implications

[en] The possible role of stars in the origin of cosmic rays is discussed in the light of the currently available knowledge on the outer layers of stars of almost all spectral types. It is suggested that galactic cosmic rays comprise the following components: (1) heavy nuclei, which would come mostly from magnetically active late-type stars through the scenario described by Meyer (1985); (2) a fraction of the p and alpha particles could come from radiatively active OB stars embedded in dense clouds; and (3) a third (minor) component would come from field OB and WR stars. One of the major problems, however, is the relative abundance of p and alpha vs heavy nuclei in galactic cosmic rays as compared to solar-type cosmic rays. 107 references

No abstract available