CONICET | Buscador de Institutos y Recursos Humanos

In observations of star-forming galaxies, a correlation between the X-ray luminosity and the star formation rate is found, with an additional effect of metallicity. X-ray binaries are assumed to be the dominant contributors, while the effect of hot gas has been estimated to vary from one galaxy to another contributing to a total X-ray luminosity by 30% in average. Green Pea galaxies are a class of star-forming galaxies with masses of ~10^9 M_sum, sub-solar metallicities, high star formation rates of ~10 M_sun/yr. With these properties, they are good analogues to high-redshift star-forming galaxies. Due to their confirmed escaping ionizing UV radiation, they serve as local laboratories for understanding the processes shaping the early Universe, namely the times of Cosmic Reionization. In recent X-ray observations of three Green Pea galaxies with XMM-Newton, an unexpected high X-ray luminosity was found in two of them, suggesting either an enhanced binary population, a large contribution of hot gas, or the presence of an AGN in these galaxies. We investigate whether the hot gas from colliding stellar winds within star clusters of these galaxies can produce enough X-ray emission to explain the excess of X-ray luminosity in the Green Pea galaxies. Following the results of recent observational studies of the mass distribution of star clusters in LEGUS dwarf galaxies, and conserving the star formation rate within the modeled galaxy, we construct a population of star clusters in dwarf galaxies. We calculate the X-ray emission from the hot gas of these star clusters using a semi-analytic model of the shocked stellar winds. According to the mass and age of the star clusters, we estimate the X-ray luminosity at different evolutionary times of the whole galaxy, by adding up the contribution of each star cluster. We further investigate the influence of the star formation rate and the metallicity of the galaxy on the results.