The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XX. Ages of single and multiple stellar populations in seven bulge globular clusters

Abstract

In the present work we analyzed seven globular clusters selected from their location in the Galactic bulge and with metallicity values in the range $-1.30\lesssim [Fe/H]\lesssim -0.50$. The aim of this work is first to derive cluster ages assuming single stellar populations, and secondly, to identify the stars from first (1G) and second generations (2G) from the main sequence, subgiant and red giant branches, and to derive their age differences. Based on a combination of UV and optical filters used in this project, we apply the Gaussian mixture models to distinguish the multiple stellar populations. Applying statistical isochrone fitting, we derive self-consistent ages, distances, metallicities, and reddening values for the sample clusters. An average of $12.3\pm 0.4$ Gyr was obtained both using Dartmouth and BaSTI (accounting atomic diffusion effects) isochrones, without a clear distinction between the moderately metal-poor and the more metal-rich bulge clusters, except for NGC 6717 and the inner halo NGC 6362 with $\sim 13.5$ Gyr. We derived a weighted mean age difference between the multiple populations hosted by each globular cluster of $41\pm 170$ Myr adopting canonical He abundances; whereas for higher He in 2G stars, this difference reduces to $17\pm 170$ Myr, but with individual uncertainties of $500$ Myr.

25 pages, 16 figures and 7 tables. Accepted for publication in ApJ

References in corpus (33)

• The Gaia mission
• The Dartmouth Stellar Evolution Database
• Fast rotating massive stars and the origin of the abundance patterns in galactic globular clusters
• Formation and Dynamical Evolution of Multiple Stellar Generations in Globular Clusters
• The ACS Survey of Galactic Globular Clusters. I. Overview and Clusters Without Previous HST Photometry
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. I. Overview of the Project and Detection of Multiple Stellar Populations
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. IX. The Atlas of Multiple Stellar Populations
• The ACS Survey of Galactic Globular Clusters. III. The Double Subgiant Branch of NGC 1851
• The double Subgiant Branch of NGC 1851: the role of the CNO abundance
• The Peculiar Horizontal Branch Morphology of the Galactic Globular Clusters NGC 6388 and NGC 6441: new insights from UV observations
• The metallicity spread and the age-metallicity relation of Omega Centauri
• The age of the young bulge-like population in the stellar system Terzan5: linking the Galactic bulge to the high-z Universe
• Physical parameters of 15 intermediate-age LMC clusters from modelling of HST colour-magnitude diagrams
• Stars caught in the braking stage in young Magellanic Clouds clusters
• The search for multiple populations in Magellanic Clouds clusters - V. Correlation between cluster age and abundance spreads
• A Deep View of a Fossil Relic in the Galactic Bulge: The Globular Cluster HP1
• The ACS Survey of Galactic Globular Clusters XIV: Bayesian Single-Population Analysis of 69 Globular Clusters
• Globular clusters in the inner Galaxy classified from dynamical orbital criteria
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters - XII. The RGB Bumps of multiple stellar populations
• Ages of the Bulge globular clusters NGC 6522 and NGC 6626 (M28) from HST Proper-motion-cleaned Color-Magnitude Diagrams
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XVIII. Proper-motion kinematics of multiple stellar populations in the core regions of NGC 6352
• A panchromatic view of the bulge globular cluster NGC 6569
• Ultra-deep GEMINI near-infrared observations of the bulge globular cluster NGC 6624
• A Highly Eccentric 3.9-Millisecond Binary Pulsar in the Globular Cluster NGC 6652
• FORS2/VLT survey of Milky Way globular clusters I. Description of the method for derivation of metal abundances in the optical and application to NGC 6528, NGC 6553, M 71, NGC 6558, NGC 6426 and Terzan 8
• The Na-O anticorrelation in horizontal branch stars. V. NGC 6723
• Abundances of disk and bulge giants from hi-res optical spectra: II. O, Mg, Ca, and Ti in the bulge sample
• Self-consistent analysis of stellar clusters: An application to HST data of the halo globular cluster NGC 6752
• Stellar abundances and ages for metal-rich Milky Way globular clusters - Stellar parameters and elemental abundances for 9 HB stars in NGC6352
• The Puzzling Negative Orbit-Period Derivative of the Low-Mass X-Ray Binary 4U 1820-30 in NGC 6624
• Chemical abundances in the metal-intermediate GC NGC 6723
• Another relic bulge globular cluster: ESO 456-SC38 (Djorgovski~2)
• Chandra Observation of Quiescent Low-Mass X-ray Binaries in the Globular Cluster NGC 6304

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