HETE-2 (High Energy Transient Explorer) is a small scientific satellite whose main task is to detect Gamma-Ray Bursts, promptly determine their coordinates, when possible, and distribute them immediately to the scientific community. HETE-2 has detected many of the most interesting events in recent years: GRB030329, which confirmed beyond any doubt

RX J1211+2242 is an optically faint (B ≃ 19.2 mag) but X-ray bright (f2 - 10 keV = 5 × 10-12 erg cm-2 s-1) AGN, which has been shown to be a BL Lac object at redshift z = 0.455. The ROSAT X-ray, Calar Alto optical, and NVSS radio data suggest that the peak of the synchrotron emission of this object is at energies as high as several keV. BeppoSAX

The metallicity distribution of stars in the Fornax dwarf spheroidal galaxy is studied with infrared Ca II triplet spectroscopy for 117 red giants, obtained with FORS1 on the VLT. The results reveal a very wide distribution of metallicities in Fornax, including a surprising abundance of young, relatively metal-rich stars ([Fe/H]>-0.7). By combining

. Superstatistics is a superposition of two different statistics relevant to driven nonequilibrium systems with a stationary state and intensive parameter fluctuations. It contains Tsallis statistics as a special case. After briefly summarizing some of the theoretical aspects, we describe recent applications of this concept to three different

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We summarize in this paper the principles for the algorithmic representation of the structure of a stellar atmosphere. The physical analysis of the problem leads to the classification of the elementary blocks that constitute a stellar atmosphere model and suggest the numerical algorithms required for its computation. Compatibly with the space