Open clusters and the structure of the Milky Way

Abstract

Our galaxy contains a large number of stellar open clusters still to be identified and characterized, but thanks to the new Gaia DR2 release, it is possible to identify new ones that are unknown to date and discard earlier reported clusters that turn out to be spurious. The aim of this work is to do a statistical analysis of the spatial and the age distribution as well as the completeness, using the most recent and comprehensive sample of open clusters available today from the Gaia satellite. Using these data and comparing them with old catalogues, we redetermine fundamental parameters of the cluster age function: logTbreak=8.52±0.18 ,α1=−0.61±0.28, α2=−1.82±0.15 for the broken power-law fit and logT∗=8.89±0.15, αT=−0.55±0.10 for the Schechter fit.