Stellar clusters in dwarf galaxiesL. Vanzi1 and M. Sauvage2
1 European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago, Chile
2 CEA/DSM/DAPNIA/Service d'Astrophysique - UMR AIM, CE Saclay, 91191 Gif-sur-Yvette Cedex, France
(Received 28 February 2005 / Accepted 13 October 2005 )
We present new observations in the (2.2 m) and L' (3.7 m) infrared bands of a sample of blue dwarf galaxies with the larger aim of studying the population of massive stellar clusters, the occurrence of dust-embedded stellar clusters, and their properties. All images show a rich population of clusters, but only a small fraction of them is bright in L'. Most L' sources have radio counterparts. We derived the luminosity function in for the galaxies IC 4661 and NGC 5408, finding both to be consistent with those of similar galaxies. We also compared the number of clusters and their luminosities with the star-formation rate of the host galaxies and found no compelling evidence of correlation. We conclude that young clusters and embedded clusters are a common feature of blue dwarf galaxies and possibly of galaxies in general, we suggest that their occurrence is due to purely statistical effects rather than a phenomenon related to specific physical conditions. In this sense we expect these objects to be abundant at high red-shift.
Key words: galaxies: dwarf -- galaxies: starburst -- galaxies: star clusters
© ESO 2006