Modeling and analysis of medium-resolution integrated-light spectra of globular clusters in dwarf galaxies

TL;DR

This paper presents a method for analyzing integrated-light spectra of globular clusters to determine their age, chemical composition, and helium content, aiding understanding of galaxy evolution.

Contribution

The study introduces a population synthesis approach that simultaneously estimates chemical composition, age, and helium fraction from spectral data, including Balmer lines.

Findings

Successfully analyzed spectra of 28 globular clusters

Determined ages, chemical compositions, and helium fractions

Enhanced understanding of multiple stellar populations

Abstract

The study of ages, helium mass fraction (Y) and chemical composition of globular clusters in dwarf galaxies is important for understanding the physical conditions at the main evolutionary stages of the host galaxies and for constraining the build-up histories of large galaxies. We present the analysis of integrated-light spectra of 8 extragalactic and 20 Galactic globular clusters (GCs) using our population synthesis method. We calculate synthetic spectra of GCs according to the defined stellar mass functions using model atmospheres and stellar parameters ($[Fe/H]$, $T_{eff}$, and $log g$) set by theoretical isochrones. The main advantage of our method is the ability to determine not only chemical composition but also the age and mean Y in a cluster by modelling and analysis of Balmer absorption lines. The knowledge of Y and anomalies of light elements in star clusters is one of the key points for understanding the phenomenon of multiple stellar populations.