Daniel Devost

Abstract

Age differences are derived between the various super star clusters of NGC 3690 using the two color diagram (B\GammaH) vs (H\GammaK) and previously published data on the physical properties of the gas. This method offers a quick and easy way to establish age differences down to a time resolution that is limited by the data on extinction. One of the infrared knots, suspected to be a galaxy nucleus, is found to be a starbursting region. The validity of the method is checked by comparing the equivalent width of the Hff line with the color maps of NGC 3690. 1. Introduction Although known to be very important in the evolution of galaxies, the star formation process is usually poorly accounted for in galactic evolution models. "Recipes" (e.g. Kennicutt 1998) are provided to account for the global characteristics of the star formation rate versus the interstellar medium (ISM); those are derived from the global or azimuthally averaged properties of observed galaxies while star formation is a ..