In an experiment described by Fishman et al. [1994], high energy photons of atmospheric origin were detected by the Burst and Transient Source Experiment (BATSE) detectors, located on the Compton Gamma Ray Observatory (CGRO). In this paper we assess the possibility that the bursts may be bremsstrahlung produced by relativistic (> 1 MeV) runaway electron beams accelerated in an avalanche process...

H.E.S.S. observations of the old-age (>10 yr; ∼ 0.5◦ diameter) composite supernova remnant (SNR) W 28 reveal very high energy (VHE) γ-ray emission situated at its northeastern and southern boundaries. The northeastern VHE source (HESS J1801−233) is in an area where W 28 is interacting with a dense molecular cloud, containing OH masers, local radio and X-ray peaks. The southern VHE sources (HESS...

Dans cet article, nous présentons tout d’abord les conceptions de l’atmosphère au xviiie siècle, en lien avec différentes acceptions la notion d’air – air grossier, pur ou subtil –, héritées pour l’essentiel Descartes, et leurs implications sur l’estimation faite à l’époque hauteur l’atmosphè...

We employ a time-dependent collisional evolution code to study the conditions under which the 50{200 km radius Edgeworth-Kuiper Objects (EKOs) in the region between 30 and 50 AU (now called the Edgeworth-Kuiper Belt, or EKB; Edgeworth 1943, 1949; Kuiper 1951) were formed. Assuming that these bodies were created by pairwise accretion from 1 to 10 km building blocks, we nd that three conditions w...

We present results of measurements of the radial extent of the accretion disc corona in low mass X-ray binaries, i.e. of the radial extent of the thin, hot ADC above the accretion disc. These results prove conclusively the extended nature of the ADC, with radial extent varying from 20,000 km in the faintest sources to 700,000 km in the brightest, a substantial fraction of the accretion disc rad...

Background: Prompt gamma neutron activation analysis (PGNAA) is known as a non-invasive technique capable of measuring elemental concentration in voluminous samples in a short period of time. Also it is a valuable diagnostic tool for total body elemental measurements. 252Cf and 241Am-Be sources which are usually used in this method, generate not only neutrons, but also emit high-energy and unwa...

ABSTRACT We have carried out a new kinematical analysis of the molecular gas in Sh2-233 region by using CO J = 2–1 data taken at ∼0.5 pc resolution. The consists filamentary cloud 5-pc length with 1.5-pc width where two dense cores are embedded. filament lies between clouds, which velocity difference 2.7 km s−1 and extended over ∼5 pc. frame scenario that clouds colliding each other compressed ...

Abstract Eruption source parameters (in particular erupted volume and column height) are used by volcanologists to inform volcanic hazard assessments classify explosive eruptions. Estimations of associated with large uncertainties due various factors, including complex tephra sedimentation patterns from gravitationally spreading umbrella clouds. We modify an advection-diffusion model investigat...

From regular monitoring of the Double Quasar QSO 0957+561 A,B there is now general agreement on a time delay of about 416 days. This has made it possible to determine the microlensing residual in the light-curve, see Pelt et al. (1998). We have used two significant microlensing features: 1) A " quiet " period with a variability less than 0.05 mag lasting about 8 years, and 2) A change in the re...

From regular monitoring of the Double Quasar QSO 0957+561 A,B there is now general agreement on a time delay of about 416 days. This has made it possible to determine the microlensing residual in the light-curve, see Pelt et al. (1998). We have used two significant microlensing features: 1) A " quiet " period with a variability less than 0.05 mag lasting about 8 years, and 2) A change in the re...