The magnetic white dwarf WD 1953-011 demonstrates the presence of two-component magnetic field geometry in photosphere. The geometry consists of a weak, large-scale component, and a strong, localized component (magnetic ``spot''). The localized component of the field is derived from variable due to the star's rotation circular polarization and

The hybrid photodetector (HPD) R9792U-40 has very high peak quantum efficiency ($>50$% at 500 nm), excellent charge resolution and very low after-pulsing probability (500 times less than that of currently used photomultipliers (PMTs)). These features will improve the sensitivity, the energy resolution and the energy threshold of the MAGIC telescope

Using original data and incorporating similar data from previous studies we investigated the effect of extra line-broadening in the atmosphere of Galactic O-stars. Our results suggest that if not taken into account, the extra broadening can lead to significant overestimation of the measured v sin i. The effect is not large (less than 30 kms), and

The question whether or not massive stars can form in isolation or only in star clusters is of great importance for the theory of (massive) star formation as well as for the stellar initial mass function of whole galaxies (IGIMF-theory). While a seemingly easy question it is rather difficult to answer. Several physical processes (e.g. star-loss due

The MAGIC experiment was upgraded to a two-telescope system in 2009. Unlike other Imaging Air Cherenkov Telescope arrays, MAGIC has operated for five years exclusively in monoscopic mode, and the single telescope analysis was optimized throughout this time. To improve the analysis, we used techniques like the random forest event classification

Multi-epoch HST images have been obtained for the pre planetary nebulae CRL618, CRL2688, and Hen3-1475. Each object shows clear and idiosyncratic expansion patterns. CRL618 consists of several well defined fingers with sharp tips. The lengths of the tips have increased by identical factors, ˜7%, over the course of seven years, suggesting a common