The neutron star X-ray transient 4U 1608-52 is often in a state of outburst (e.g. ATel #1113); the Swift/BAT light curve shows three clear outburst peaks so far in 2009. The source usually remains in a hard X-ray state during its outbursts. Here we report an X-ray state transition to a soft state around MJD 54960-75 (2009-05-09 - 24) and

Post common envelope binaries (PCEBs) consisting of a white dwarf and a main sequence star are ideal systems to calibrate current theories of angular momentum loss in close compact binary stars. The potential held by PCEBs for further development of close binary evolution could so far not be exploited due to the small number of known systems and

We present the result of the observation of the ultrafaint dwarf galaxy Willman 1 performed with the 17 m MAGIC telescope during 15.5 hr between March and May 2008. No significant γ-ray emission was found. We derived upper limits of the order of 10-12 ph cm-2 s-1 on the integral flux above 100 GeV, which we compare with predictions from several of

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Here we present multilevel radiative transfer calculations of the scattering polarization of neutral titanium lines in a three-dimensional model of the solar photosphere, which we have obtained from realistic hydrodynamical simulations of solar surface convection. We consider the particularly interesting case of the Ti I multiplet a{^5}F - y{^5}Fo

We identify SDSS 0110+1326, SDSS 0303+0054 and SDSS 1435+3733 as three eclipsing white dwarf plus main sequence binaries from the Sloan Digital Sky Survey, and report on their follow-up observations. Orbital periods for the three systems are established through multi-season photometry. Time-resolved spectroscopic observations lead to the