Evolutionary synthesis of simple stellar populations

Colours and indices

Universitätssternwarte Göttingen, Geismarlandstr. 11, 37083 Göttingen, Germany e-mail: okurth@uni-sw.gwdg.de

Send offprint request to: O. Kurth

Received: 16 March 1998
Accepted: 11 February 1999

Abstract

We construct evolutionary synthesis models for simple stellar populations using the evolutionary tracks from the Padova group (1993, 1994), theoretical colour calibrations from [Lejeune et al. (1997, 1998)] and fit functions for stellar atmospheric indices from [Worthey et al. (1994)]. A Monte-Carlo technique allows us to obtain a smooth time evolution of both broad band colours in UBVRIK and a series of stellar absorption features for Single Burst Stellar Populations (SSPs). We present colours and indices for SSPs with ages from  yrs to  yrs and metallicities , -1.7, -0.7, -0.4, 0.0 and 0.4. Model colours and indices at an age of about a Hubble time are in good agreement with observed colours and indices of the Galactic and M 31 GCs.