We present a high-resolution multi-frequency identification study of the Small Magellanic Cloud (SMC) region around the newly discovered X-ray pulsar AX J0049-732. ROSAT PSPC images show three X-ray sources near the ASCA source position. We combine X-ray, radio-continuum and optical data to identify these sources. RX J0049.2-7311 and RX J0049.5-7310 did not show long-term time variability nor p...

The distance to the M supergiant Betelgeuse is poorly known, with the Hipparcos parallax having a significant uncertainty. For detailed numerical studies of M supergiant atmospheres and winds, accurate distances are a prerequisite to obtaining reliable estimates for many stellar parameters. New high spatial resolution, multiwavelength, NRAO3 Very Large Array (VLA) radio positions of Betelgeuse ...

Methanol masers are often detected in regions of intense star formation. Several studies in the last decade indicate that they may even be the earliest signpost of a high-mass star-forming region. Their powerful emission make them very good candidates for observations using both single–dish telescopes and interferometers, the latter allows detailed structural and dynamical studies of these obje...

Aims. We search for very small-diameter galactic planetary nebulae (PNe) representing the earliest phases of PN evolution. The IPHAS catalogue of Ha-emitting stars provides a useful basis for this study since all sources present in this catalogue must be of small angular diameter. Methods. The PN candidates are selected based on their location in two colour-colour diagrams: IPHAS (Z Ha) vs. (Z ...

In the ROSAT Bright Survey (RBS) we have almost completely optically identified the brightest ∼2000 high-galactic latitude sources from the ROSAT All-Sky Survey Bright Source Catalogue (1RXS). A small number of sources has empty X-ray error circles on optical images. ROSAT HRI follow-up observations of RBS1223 (=1RXS J130848.6+212708), a soft object with extreme X-ray to optical flux ratio, hav...

Methanol masers are often detected in regions of intense star formation. Several studies in the last decade indicate that they may even be the earliest signpost of a high-mass star-forming region. Their powerful emission make them very good candidates for observations using both single-dish telescopes and interferometers, the latter allows detailed structural and dynamical studies of these obje...

In order to evaluate and develop mission concepts for a search for Terrestrial Exoplanets, we have prepared a list of potential target systems. In this paper we present and discuss the criteria for selecting potential target stars suitable for the search for Earth like planets, with a special emphasis on the aspects of the habitable zone for these stellar systems. Planets found within these zon...