To explain the currently observed accelerated expansion of the universe, a large number of different theoretical models are presently being discussed. In one way or another, all of these contain `new physics', though at different levels. The big question is how to select out of infinitely many possible models the right one. We here discuss a

We present the results from our non-LTE investigation for neutral carbon, which was carried out to remove potential systematic errors in stellar abundance analyses. The calculations were performed for late-type stars and give substantial negative non-LTE abundance corrections. When applied to observations of extremely metal-poor stars, which within

We have developed TGMETalpha in order to determine T_{eff}, log g, [Fe/H] and [alpha /Fe] for large samples of FGK stars observed at various spectral resolutions. Tests on several hundred echelle spectra of reference stars degraded to low resolution (R=1.000) indicate typical rms precisions of sigma (T_{eff})˜150 K, sigma (logg)˜0.44, sigma ([Fe/H]

We present accurate B, V, R photometry of the Sculptor dwarf spheroidal galaxy. The data have been collected with the Wide Field Imager available at 2.2 m ESO/MPI telescope and cover an area of about 100×40 arcmin2 around the Sculptor center. The final catalogue includes 100,000 stars. We found that blue and red Horizontal Branch stars present

Not Available

Microquasars are in many ways similar to their massive counterparts, the radio loud population of AGNs. One aspect that is just beginning to receive the due amount of attention is their interaction with the interstellar medium. This interaction is similar on a qualitative level, but different quantitatively: The interstellar medium provides a much