We have obtained HST-NICMOS observations of five of M31's most metal rich globular clusters: G1, G170, G174, G177 & G280. In order to disentangle the true properties of the population from the observational effects associated with measurements made in very crowded fields, we first present a careful analysis of photometry in crowded regions. Here we

The Andromeda Galaxy recurrent nova M31N 2008-12a had been observed in eruption 10 times, including yearly eruptions from 2008 to 2014. With a measured recurrence period of {P}{rec}=351+/- 13 days (we believe the true value to be half of this) and a white dwarf very close to the Chandrasekhar limit, M31N 2008-12a has become the leading pre

This work presents a low resolution spectroscopic data analisis of HII regions in the magellanic clouds. Nineteen nights of data over five observing seasons were analyzed to obtain the spectrums of planetary nebulae,supernova remnants, single star shells, bubbles, superbubbles and the interstellar medium. This investigation is part of the more

We report on the observation of the region around supernova remnant G65.1+0.6 with the stand-alone MAGIC-I telescope. This region hosts the two bright GeV gamma-ray sources 1FGL J1954.3+2836 and 1FGL J1958.6+2845. They are identified as GeV pulsars and both have a possible counterpart detected at about 35 TeV by the Milagro observatory. MAGIC

Magnetic fields not only provide a basic tool for observing galaxies but constitute an important clue to interpret many dynamic processes taking place in them, mainly in spiral and irregular galaxies. As in the Sun, magnetic fields become important where gravity becomes lower, i.e. in the outermost regions. Any peripheric feature should be

The quiet Sun photospheric plasma has a variety of magnetic field strengths going from zero to 1800 G. The empirical characterization of these field strengths requires a probability density function (PDF), i.e., a function P(B) describing the fraction of quiet Sun occupied by each field strength B. We present a method to combine magnetic field