On the mass and wind luminosity of young Galactic open clusters in Gaia DR2

Context. Star clusters constitute a relevant part of the stellar population in our Galaxy. The feedback processes they exert on the interstellar medium impact multiple physical processes, from the chemical to the dynamical evolution of the Galaxy. In addition, young and massive stellar clusters might act as efficient particle accelerators, possibly contributing to the production of cosmic rays. Aims. We aim at evaluating the wind luminosity driven by the young (< 30 Myr) Galactic open stellar clusters observed by the Gaia space mission, which is crucial to determine the energy channeled into accelerated particles. Methods. To this extent, we develop a method relying on the number, magnitude and line-of-sight extinction of the stars observed per cluster. Assuming that the stellar mass function follows a Kroupa mass distribution, and accounting for the maximum stellar mass allowed by both the parent cluster age and mass, we conservatively estimate the mass and wind luminosity of 387 local clusters within the second data release of Gaia. Results. We compare the results of our computation with recent estimations of young cluster masses. With respect to these, we provide a sample three times more abundant, particularly above a few thousand solar masses, which is of the utmost relevance for predicting the gamma-ray emission resulting from the interaction of accelerated particles. In fact, the cluster wind luminosity distribution we obtain is found to extend up to 3 x 10^38 erg/s, a promising feature in terms of potential particle acceleration scenarios.Comment: 11 pages, 16 figures, comments are welcom