We present an INTEGRAL data analysis of the X-ray transient SAX J2103.5+4545 during December 2002. The source showed two type-I outbursts in this period. The INTEGRAL location agrees with the position of the recently proposed optical counterpart. A power-law model was fitted to the 10 100 keV spectrum and a photon index of 2.5±0.1 was derived. The

We present observational evidence, from Hαin face-on galaxies, which strongly favours the hypothesis that escaping photons from H II regions are the basic cause of the ionization of the diffuse ionized gas in galaxy discs, and by implication are the chief cause of the Reynolds layer in the Milky Way, and refer the reader to models based on these

The enhancement factor to the thermonuclear reaction rate in the center of the Sun is calculated using the Feynman-Kac path integral of the grand-canonical partition function. Using the generalized virial expansion for a multicomponent quantum plasma, we have calculated the truncated pair distribution function for solar conditions up to the order

We introduce a new scheme to study the nature of the central engine in a lensed QSO. The compact emission regions could have different sizes in different optical wavelengths, and our framework permits us to obtain the source size ratios when a microlensing special high-magnification event (e.g., a caustic crossing event, a two-dimensional maximum

GREGOR is the new 1.5 m solar telescope assembled on Tenerife, Spain, by the German consortium of the Kiepenheuer Institut fur Sonnenphysik, the Astronomischen Institut Potsdam, the Universitats-Sternwarte Gottingen and other national and international Partners. The refurbishment of the building is almost finished. The manufacturing of the

The 10m Gran Telescopio Canarias (GTC) is currently being installed in the Observatorio del Roque de los Muchachos (ORM) on the island of La Palma. An adaptive optics (AO) system will be installed at one of the Nasmyth foci of the telescope within a year of the telescope being commissioned. The preliminary design of the adaptive optics system is