OB stars at the lowest Local Group metallicity: GTC-OSIRIS observations of Sextans A

Our aim is to find and classify OB stars in Sextans A, to later determine accurate stellar parameters of these blue massive stars in this low metallicity region $(Z \sim 0.1 \rm Z_{\odot})$. Using UBV photometry, the reddening-free index Q and GALEX imaging, we built a list of blue massive star candidates in Sextans A. We obtained low resolution (R $\sim$ 1000) GTC-OSIRIS spectra for a fraction of them and carried out spectral classification. For the confirmed O-stars we derive preliminary stellar parameters. The target selection criteria and observations were successful and have produced the first spectroscopic atlas of OB-type stars in Sextans A. From the whole sample of 18 observed stars, 12 were classified as early OB-types, including 5 O-stars. The radial velocities of all target stars are in agreement with their Sextans A membership, although three of them show significant deviations. We determined the stellar parameters of the O-type stars using the stellar atmosphere code FASTWIND, and revisited the sub-SMC temperature scale. Two of the O-stars are consistent with relatively strong winds and enhanced helium abundances, although results are not conclusive. We discuss the position of the OB stars in the HRD. Initial stellar masses run from slightly below 20 up to 40 solar masses. The target selection method worked well for Sextans A, confirming the procedure developed in Garcia \& Herrero (2013). The stellar temperatures are consistent with findings in other galaxies. Some of the targets deserve follow-up spectroscopy because of indications of a runaway nature, an enhanced helium abundance or a relatively strong wind. We observe a correlation between HI and OB associations similar to the irregular galaxy IC1613, confirming the previous result that the most recent star formation of Sextans A is currently on-going near the rim of the H\,{\sc I} cavity

Los desterrados catalanes en Italia durante la Guerra de Separación de Catalunya (1640-1652)

Desde mediados de 1642 hasta la caída de Barcelona en manos españolas en octubre de 1652, un grupo de catalanes, la mayoría de ellos perteneciente a la clase dirigente del Principado, fue desterrado a Italia por la administración francesa. En este artículo, a partir del fenómeno del destierro, intentaremos analizar las estrategias seguidas por los gobiernos de Madrid y París respecto a la clase dirigente catalana que había liderado el proceso revolucionario de 1640-1641.From halfway through 1642 to Barcelona’s fall in October 1652, a group of Catalan people, who mainly belonged to the Catalan ruling class, was exiled to Italy by the French government. In this article, starting from this exile phenomenon, I try to analyse the political strategies followed by the Madrid and Paris governments regarding the Catalan ruling class, which played the leading role in the revolutionary process of 1640-1641