SCYON Abstract

Received on October 6 2009

A Bayesian Approach Accounting for Stochastic fluctuations in Stellar Cluster Properties

AuthorsM. Fouesneau and A. Lançon
AffiliationObservatoire Astronomique (UMR 7550), Université de Strasbourg & CNRS, 11 rue de l'Université, 67000 Strasbourg, France
To appear inGalaxy Wars: Stellar Populations and Star Formation in Interacting Galaxies Conference
Contactmorgan.fouesneau@astro.u-strasbg.fr
URLhttp://arxiv.org/abs/0908.2742v1
Links

Abstract

The integrated spectro-photometric properties of star clusters are subject to large cluster-to-cluster variations. They are distributed in non trivial ways around the average properties predicted by standard population synthesis models. This results from the stochastic mass distribution of the finite (small) number of luminous stars in each cluster, stars which may be either particularly blue or particularly red. The color distributions are broad and usually far from Gaussian, especially for young and intermediate age clusters, as found in interacting galaxies. When photometric measurements of clusters are used to estimate ages and masses in conjunction with standard models, biases are to be expected. We present a Bayesian approach that explicitly accounts for stochasticity when estimating ages and masses of star clusters that cannot be resolved into stars. Based on Monte-Carlo simulations, we are starting to explore the probability distributions of star cluster properties obtained given a set of multi-wavelength photometric data.