Detailed AGB evolutionary models and near infrared colours of intermediate-age stellar populations: Tests on star clusters

Abstract

We investigate the influence of Asymptotic Giant Branch stars on integrated colours of star clusters of ages between ~100 Myr and a few gigayears, and composition typical for the Magellanic Clouds. We use state-of-the-art stellar evolution models that cover the full thermal pulse phase, and take into account the influence of dusty envelopes on the emerging spectra. We present an alternative approach to the usual isochrone method, and compute integrated fluxes and colours using a Monte Carlo technique that enables us to take into account statistical fluctuations due to the typical small number of cluster stars. We demonstrate how the statistical variations in the number of Asymptotic Giant Branch stars and the temperature and luminosity variations during thermal pulses fundamentally limit the accuracy of the comparison (and calibration, for population synthesis models that require a calibration of the Asymptotic Giant Branch contribution to the total luminosity) with star cluster integrated photometries. When compared to observed integrated colours of individual and stacked clusters in the Magellanic Clouds, our predictions match well most of the observations, when statistical fluctuations are taken into account, although there are discrepancies in narrow age ranges with some (but not all) set of observations.

12 pages, 14 figures, accepted for publication in A&A

References in corpus (7)

• Evolution of asymptotic giant branch stars I. Updated synthetic TP-AGB models and their basic calibration
• A Large Stellar Evolution Database for Population Synthesis Studies. III. Inclusion of the full Asymptotic Giant Branch phase and Web tools for stellar population analyses
• A large stellar evolution database for population synthesis studies. IV. Integrated properties and spectra
• A Comparison of Optical and Near-Infrared Colours of Magellanic Cloud Star Clusters with Predictions of Simple Stellar Population Models
• Joint Analysis of near-infrared properties and surface brightness fluctuations of LMC star clusters
• Red Giant stars in the Large Magellanic Cloud clusters
• A Database of 2MASS Near-Infrared Colors of Magellanic Cloud Star Clusters

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