Bayesian Analysis of Two Stellar Populations in Galactic Globular Clusters II: NGC 5024, NGC 5272, and NGC 6352

Rachel Wagner-Kaiser, Ted von Hippel, David Stenning, Elliot Robinson, Ata Sarajedini, David van Dyk, Nathan Stein, William H. Jefferys

Research output: Contribution to journalArticlepeer-review

Abstract

We use Cycle 21 Hubble Space Telescope (HST) observations and HST archival ACS Treasury observations of Galactic Globular Clusters to find and characterize two stellar populations in NGC 5024 (M53), NGC 5272 (M3), and NGC 6352. For these three clusters, both single and double-population analyses are used to determine a best fit isochrone(s). We employ a sophisticated Bayesian analysis technique to simultaneously fit the cluster parameters (age, distance, absorption, and metallicity) that characterize each cluster. For the two-population analysis, unique population level helium values are also fit to each distinct population of the cluster and the relative proportions of the populations are determined. We find differences in helium ranging from 0.05 to 0.11 for these three clusters. Model grids with solar a-element abundances ([a/Fe] =0.0) and enhanced a-elements ([a/Fe]=0.4) are adopted.

Original languageAmerican English
JournalThe Astrophysical Journal
Volume826
DOIs
StatePublished - Nov 9 2018

Keywords

  • globular clusters: general
  • globular clusters: individual (NGC 5024
  • NGC 5272
  • NGC 6352)

Disciplines

  • Stars, Interstellar Medium and the Galaxy

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