Aims: We obtained phase-resolved spectroscopy of the accreting millisecond X-ray pulsar SAX J1808.4-3658 during its outburst in 2008 to find a signature of the donor star, constrain its radial velocity semi-amplitude (K_2), and derive estimates for the pulsar mass. Methods: Using Doppler images of the Bowen region, we find a significant (≥8σ)

In the coming years, several cosmological surveys will rely on imaging data to estimate the redshift of galaxies, using traditional filter systems with 4-5 optical broad bands; narrower filters improve the spectral resolution, but strongly reduce the total system throughput. We explore how photometric redshift performance depends on the number of

We present long-slit intermediate resolution spectroscopy of the visual binary V1123. We confirm that component A is a W UMa eclipsing star with spectral type G0V, while component B is a K0V. We infer a distance to the system of 125 pc, and then a projected separation between both components of 520 AU. The difference in radial velocities of

Context: Early-type dwarf (dE) galaxies are the most common type of galaxies observed in the Universe. Their study has important cosmological implications because according to hierarchical galaxy evolution theories they are the progenitors of brighter galaxies. Nevertheless, the origin of this kind of system is still not well understood. Aims: The

A survey of Ne, O and Fe coronal abundances culled from the recent literature for about 60 late-type stars confirms that the Ne/O ratio of stellar outer atmospheres is about two times the value recently recommended by Asplund et al. The mean Ne/O remains flat from the most active stars down to at least intermediate activity levels (-5

A few nearby interacting galaxies are known that host elevated numbers of ultraluminous X-ray sources. Here we report the results of a multiwavelength study of the X-ray source population in the field of the interacting pair of galaxies NGC 5774/5775. A total of 49 discrete sources are detected, including 12 ultraluminous X-ray source candidates