MIUSCAT: extended MILES spectral coverage. II. Constraints from optical photometry

TL;DR

This paper evaluates the MIUSCAT stellar population synthesis models against optical photometry data of globular clusters and early-type galaxies, highlighting their strengths and current limitations in matching observed galaxy colours.

Contribution

It provides a comprehensive comparison of MIUSCAT models with photometric data, emphasizing the importance of alpha-enhancement to improve model accuracy.

Findings

Models match Milky Way globular cluster colours well.

Younger ages explain M31 globular cluster colours.

Alpha-enhanced models reduce discrepancies with galaxy observations.

Abstract

In the present work we show a comprehensive comparison of our new stellar population synthesis MIUSCAT models with photometric data of globular clusters and early-type galaxies. The models compare remarkably well with the colours of Milky Way globular clusters in the optical range. Likewise, the colours of M31 globular clusters can also be explained by the models by assuming younger ages then their Galactic counterparts. When compared with quiescent galaxies we reproduce the colour evolution at intermediate redshift. On the other hand we find that the colour relations of nearby early-type galaxies are still a challenge for present-day stellar population synthesis models. We investigate a number of possible explanations and establish the importance of alpha-enhanced models to bring down the discrepancy with observations.