A new catalog of homogenised absorption line indices for Milky Way globular clusters from high-resolution integrated spectroscopy

TL;DR

This paper presents a comprehensive catalog of homogenized absorption line indices for 53 Milky Way globular clusters, derived from high-resolution integrated spectroscopy, aiding in metallicity estimation of unresolved stellar systems.

Contribution

It introduces a new, large database of Lick spectral indices for globular clusters, combining new observations with existing data, and provides empirical index-to-metallicity relations.

Findings

Constructed a database of 53 globular clusters with diverse metallicities.

Provided empirical relationships for metallicity estimation from spectral indices.

Achieved high-resolution spectral measurements across multiple clusters.

Abstract

We perform integrated spectroscopy of 24 Galactic globular clusters. Spectra are observed from one core radius for each cluster with a high wavelength resolution of ~2.0 A FWHM. In combination with two existing data sets from Puzia et al. (2002) and Schiavon et al. (2005), we construct a large database of Lick spectral indices for a total of 53 Galactic globular clusters with a wide range of metallicities, -2.4 < [Fe/H] < 0.1, and various horizontal-branch morphologies. The empirical index-to-metallicity conversion relationships are provided for the 20 Lick indices for the use of deriving metallicities for remote, unresolved stellar systems.