We present simultaneous high-resolution optical spectroscopy and X-ray data of the X-ray binary system GRMus (XB1254-690), obtained over a full range of orbital phases. The X-ray observations are used to re-establish the orbital ephemeris for this source. The optical data include the first spectroscopic detection of the donor star in this system

We analyze evolution of live disk-halo systems with gas fractions, fgas

Aims:We investigate the statistical properties of the extreme events of the solar cycle as measured by the sunspot number. Methods: The recent advances in the methodology of the theory of extreme values are applied to the maximal extremes of the time series of sunspots. We focus on the extreme events that exceed a carefully chosen threshold and a

We study the emergence of magnetic flux at very small spatial scales (less than 2") in the quiet-Sun internetwork. To this aim, a time series of spectropolarimetric maps was taken at disk center using the instrument SP/SOT on board Hinode. The LTE inversion of the full Stokes vector measured in the Fe I 6301 and 6302 Å lines allows us to retrieve

Aims:We aim to identify the nature of several objects previously catalogued as ultra-luminous X-ray (ULX) source candidates. Methods: Long-slit spectroscopy of the optical counterparts has been carried out. Results: The eight objects are at higher redshift than their putative parent galaxies. Conclusions: It is found that these eight previously

Transiting extrasolar planets constitute only a small fraction of the range of stellar systems found to display periodic, shallow dimmings in wide-field surveys employing small-aperture camera arrays. Here we present an efficient selection strategy for follow-up observations, derived from analysis of the light curves of a sample of 67 SuperWASP