Una revisión de la clasificación de fuentes de rayos X de la galaxia empleando datos de Gaia y TESS

Abstract

X-ray astronomy has grown very fast in the last decades thanks to the development of several space-missions that have detected more than half a million high-energy sources. Among these, X-ray binaries stand out as the brightest objects in this electromagnetic range in our Galaxy. Such systems are composed of a stellar remnant (white dwarf, neutron star or a black hole) and a companion star with the emission in X-rays due to the accretion of matter onto the compact object. The classification of these accreting X-ray binaries is based on the compact object nature, spectral type of the donor star and the mode of mass transfer. In this way, accreting systems are classified into cataclysmic variables, and high-mass and low-mass X-ray binaries. Another type of X-ray binaries are the chromospherically active systems. They are characterized by strong chromosphere and coronal activity where the X-ray emission is powered by the rapid rotation of the stellar components. In this class, depending on the stars evolutionary state and whether they fill their Roche lobes, we can distinguish between the RS CVn and contact binaries. Different observational techniques allow us to classify, or at least put a constraint on the binary type via, for instance, the identification of certain emission and absorption lines in their spectra, the detection of the rotational period of the compact object at X-rays, or the light curve morphology at optical wavelengths.