Evidence for Enrichment by Supernovae in the Globular Cluster NGC 6273

Abstract

In our recent investigation (Lim et al. 2015), we have shown that narrow-band photometry can be combined with low-resolution spectroscopy to effectively search for globular clusters (GCs) with supernovae (SNe) enrichments. Here we apply this technique to the metal-poor bulge GC NGC 6273, and find that the red giant branch stars in this GC are clearly divided into two distinct subpopulations having different calcium abun- dances. The Ca rich subpopulation in this GC is also enhanced in CN and CH, showing a positive correlation between them. This trend is identical to the result we found in M22, suggesting that this might be a ubiquitous nature of GCs more strongly affected by SNe in their chemical evolution. Our results suggest that NGC 6273 was massive enough to retain SNe ejecta which would place this cluster in the growing group of GCs with Galactic building block characteristics, such as ω Centauri and Terzan 5.

5 pages, 5 figures, accepted for the publication in ApJL

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Cited by in corpus (7)

• A Chemical Composition Survey of the Iron-Complex Globular Cluster NGC 6273 (M 19)
• Reversed radial distribution trend of subpopulations in the globular clusters NGC 362 and NGC 6723
• Confirming the intrinsic abundance spread in the globular cluster NGC 6273 (M 19) with calcium triplet spectroscopy
• The CN-CH positive correlation in the globular cluster NGC 5286
• RR Lyrae Variable Stars in the Crater II Dwarf Galaxy
• Narrowband Ca Photometry for Dwarf Spheroidal Galaxies. I. Chemostructural Study on Draco, Sextans, and Canes Venatici I
• New sub-grouping of multiple stellar populations in NGC 2808 based on low-resolution spectroscopy