Catalog of Chromium, Cobalt, and Nickel Abundances in Globular Clusters and Dwarf Galaxies

TL;DR

This paper provides a comprehensive catalog of chromium, cobalt, and nickel abundances in over 4,000 stars across globular clusters, dwarf galaxies, and field stars, using medium-resolution spectroscopy to analyze chemical compositions.

Contribution

It presents a large, homogeneous dataset of element abundances in diverse stellar populations, validated with high-resolution comparisons and systematic error estimates.

Findings

Median uncertainties are 0.20 for Cr/Fe and Co/Fe, and 0.13 for Ni/Fe.

Abundance measurements are validated against high-resolution spectra.

Systematic errors are estimated from dispersion within globular clusters.

Abstract

We present measurements of the abundances of chromium, cobalt, and nickel in 4113 red giants, including 2277 stars in globular clusters, 1820 stars in the Milky Way's dwarf satellite galaxies, and 16 field stars. We measured the abundances from mostly archival Keck/DEIMOS medium-resolution spectroscopy with a resolving power of R ~ 6500 and a wavelength range of approximately 6500-9000 A. The abundances were determined by fitting spectral regions that contain absorption lines of the elements under consideration. We used estimates of temperature, surface gravity, and metallicity that we previously determined from the same spectra. We estimated systematic error by examining the dispersion of abundances within mono-metallic globular clusters. The median uncertainties for [Cr/Fe], [Co/Fe], and [Ni/Fe] are 0.20, 0.20, and 0.13, respectively. Finally, we validated our estimations of uncertainty through duplicate measurements, and we evaluated the accuracy and precision of our measurements through comparison to high-resolution spectroscopic measurements of the same stars.