On the morphology of open clusters probed by ASteCA using Gaia data

Abstract

We analyze the morphology of over 1000 open clusters scattered in the third and fourth quadrants of the Galaxy, obtaining estimates for their projected two-dimensional ellipticities and rotation angles. Both parameters are closely linked to the formation process and dynamical evolution of these objects. We employed a Bayesian inference method combined with a generalized King profile model through our Automated Stellar Cluster Analysis (ASteCA) tool. The data come from the latest Gaia release to date (DR3), up to a magnitude of G=19. Analysis of hundreds of synthetic clusters indicates that our approach is considerably more precise and robust than the usual method of fitting an ellipse to a subset of selected members using the singular value decomposition method.