We present simultaneous X-ray (RXTE) and optical (ULTRACAM) narrow-band (Bowen blend/HeII and nearby continuum) observations of Sco X-1 at 2-10 Hz time resolution. We find that the Bowen/HeII emission lags the X-ray light curves with a light traveltime of s which is consistent with reprocessing in the companion star. The echo from the donor is

We report the detection of a new source of very high energy (VHE; Eγ>=100 GeV) γ-ray emission located close to the Galactic plane, MAGIC J0616+225, which is spatially coincident with supernova remnant IC 443. The observations were carried out with the MAGIC telescope in the periods 2005 December-2006 January and 2006 December-2007 January. Here we

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The dynamics of a barred galaxy depends on the pattern speed of its bar. The only direct method for measuring the pattern speed of a bar is the Tremaine-Weinberg technique. This method is best suited to the analysis of the distribution and dynamics of the stellar component. Therefore it has been mostly used for early-type barred galaxies. Nearly

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Recent studies of the near-infrared (NIR) properties of dwarf irregular galaxies (dIs) and blue compact dwarfs (BCDs) have provided improved estimates for the NIR luminosity of old stellar populations in these galaxies. These can be used to derive gas fractions, and thereby to evaluate how BCDs have evolved with respect to dIs. Oxygen abundances