The Effect of Binary Interactions in Infrared Passbands

TL;DR

This study investigates how binary interactions influence infrared magnitudes and colours in stellar populations, showing that including binaries results in brighter magnitudes and bluer colours for populations older than 1 Gyr, and improves model-observation agreement.

Contribution

It provides new integrated infrared magnitudes and colours for binary stellar populations, highlighting the impact of binary interactions and comparing results with existing models and observations.

Findings

Binary interactions make magnitudes larger and colours bluer for >1 Gyr populations.

Models with binary interactions better match observed globular cluster colours.

Comparison with BC03 and M05 models shows improved agreement with observations.

Abstract

We present the integrated J, H, K, L, M and N magnitudes and the colours involving infrared bands, for an extensive set of instantaneous-burst binary stellar populations (BSPs) by using evolutionary population synthesis (EPS). By comparing the results for BSPs WITH and WITHOUT binary interactions we show that the inclusion of binary interactions makes the magnitudes of populations larger (fainter) and the integrated colours smaller (bluer) for t > 1Gyr. Also, we compare our model magnitudes and colours with those of Bruzual & Charlot (2003, hereafter BC03) and Maraston (2005, hereafter M05). At last, we compare these model broad colours with Magellanic Clouds globular clusters (GCs) and Milky Way GCs. In (V-R)-[Fe/H] and (V-I)-[Fe/H] diagrams it seems that our models match the observations better than those of BC03 and M05.