An intermediate-band photometric study of the "Globular Cluster" NGC 2419

TL;DR

This study uses deep intermediate-band photometry to investigate the chemical composition and stellar populations of the remote globular cluster NGC 2419, shedding light on its possible extragalactic origins.

Contribution

It introduces the first application of well-calibrated Stroemgren indices to analyze chemical variations and multiple populations in NGC 2419.

Findings

Detection of potential chemical abundance variations.

Evidence supporting multiple stellar populations.

Insights into the cluster's possible extragalactic origin.

Abstract

NGC 2419 is one of the remotest star clusters in the Milky Way halo and its exact nature is yet unclear: While it has traits reminiscent of a globular cluster (GC), its large radius and suggestions of an abundance spread have fueled the discussion about its origin in an extragalactic environment, possibly the remnants of the accretion of a dwarf galaxy. Here, we present first results from deep intermediate-band photometry of NGC 2419, which enables us to search for chemical (light element) abundance variations, metallicity spreads, and thus multiple stellar populations through well calibrated Stroemgren indices.