On a new Near-Infrared method to estimate the absolute ages of star clusters: NGC3201 as a first test case

Abstract

We present a new method to estimate the absolute ages of stellar systems. This method is based on the difference in magnitude between the main sequence turn-off (MSTO) and a well defined knee located along the lower main sequence (MSK). This feature is caused by the collisionally induced absorption of molecular hydrogen and it can be easily identified in near-infrared (NIR) and in optical-NIR color-magnitude diagrams of stellar systems. We took advantage of deep and accurate NIR images collected with the Multi-Conjugate Adaptive Optics Demonstrator temporarily available on the Very Large Telescope and of optical images collected with the Advanced Camera for Surveys Wide Field Camera on the Hubble Space Telescope and with ground-based telescopes to estimate the absolute age of the globular NGC3201 using both the MSTO and the Delta(MSTO-MSK). We have adopted a new set of cluster isochrones and we found that the absolute ages based on the two methods agree to within one sigma. However, the errors of the ages based on the Delta(MSTO-MSK) method are potentially more than a factor of two smaller, since they are not affected by uncertainties in cluster distance or reddening.Current isochrones appear to predict slightly bluer (~0.05mag) NIR and optical-NIR colors than observed for magnitudes fainter than the MSK.

8 pages, 4 figures, accepted for publication on ApJL

References in corpus (8)

• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The Dartmouth Stellar Evolution Database
• The Evolution of L and T Dwarfs in Color-Magnitude Diagrams
• Atomic Diffusion and Mixing in Old Stars I. VLT/FLAMES-UVES Observations of Stars in NGC 6397
• Deep ACS Imaging in the Globular Cluster NGC 6397: The Cluster Color Magnitude Diagram and Luminosity Function
• Probing the Faintest Stars in a Globular Star Cluster
• On the Use of Blanketed Atmospheres as Boundary Conditions for Stellar Evolutionary Models
• Relative distances of Omega Centauri and 47 Tucanae

Cited by in corpus (45)

• Mean proper motions, space orbits and velocity dispersion profiles of Galactic globular clusters derived from Gaia DR2 data
• Origin of the system of globular clusters in the Milky Way
• Accurate distances to Galactic globular clusters through a combination of Gaia EDR3, HST and literature data
• Adaptive Optics for Astronomy
• Globular Cluster Formation and Evolution in the Context of Cosmological Galaxy Assembly: Open Questions
• On the distance of the globular cluster M4 (NGC 6121) using RR Lyrae stars: I. optical and near-infrared Period-Luminosity and Period-Wesenheit relations
• Constraining stellar population models - I. Age, metallicity, and abundance pattern compilation for Galactic globular clusters
• The infrared eye of the Wide-Field Camera 3 on the Hubble Space Telescope reveals multiple main sequences of very low-mass stars in NGC 2808
• On the RR Lyrae stars in globulars: IV. $\omega$ Centauri Optical UBVRI Photometry
• GLIMPSE-CO1: the most massive intermediate-age stellar cluster in the Galaxy
• The WFC3 Galactic Bulge Treasury Program: Metallicity Estimates for the Stellar Population and Exoplanet Hosts
• Is there a concordance value for $H_0$?
• A Deep, Wide-Field, and Panchromatic View of 47 Tuc and the SMC with HST: Observations and Data Analysis Methods
• Distance to Galactic globulars using the near-infrared magnitudes of RR Lyrae stars: IV. The case of M5 (NGC5904)
• Constraining Globular Cluster Age Uncertainties Using the IR Color-Magnitude Diagram
• A Fossil Bulge Globular Cluster revealed by VLT Multi-Conjugate Adaptive Optics
• GeMS MCAO observations of the Galactic globular cluster NGC 2808: the absolute age
• Ultra-deep GEMINI near-infrared observations of the bulge globular cluster NGC 6624
• On the distance of the globular cluster M4 (NGC 6121) using RR Lyrae stars: II. Mid-infrared period-luminosity relations
• On the kinematic separation of field and cluster stars across the Bulge globular NGC 6528
• Constraints on the Cosmological Coupling of Black Holes from the Globular Cluster NGC 3201
• Towards Precision Photometry with Extremely Large Telescopes: the Double Subgiant Branch of NGC 1851
• The Age of the Old Metal-Poor Globular Cluster NGC6397 Using WFC3/IR Photometry
• The absolute age of the globular cluster M15 using near-infrared adaptive optics images from PISCES/LBT
• GeMS/GSAOI photometric and astrometric performance in dense stellar fields
• Stroemgren - near-infrared photometry of the Baade's Window. I. The bulge globular cluster NGC6528 and the surrounding field
• On the absolute age of the metal-rich globular M71 (NGC 6838): I. optical photometry
• On the white dwarf cooling sequence with extremely large telescopes
• A method for space-variant deblurring with application to adaptive optics imaging in astronomy
• The GeMS/GSAOI Galactic Globular Cluster Survey (G4CS) I: A Pilot Study of the stellar populations in NGC 2298 and NGC 3201
• Disintegration of the Aged Open Cluster Berkeley 17
• Cool Subdwarf Investigations III: Dynamical Masses of Low Metallicity Subdwarfs
• Cosmological constraints from low-redshift data
• Euclid: Early Release Observations -- Unveiling the morphology of two Milky Way globular clusters out to their periphery
• On the use of the main sequence knee (saddle) to measure globular cluster ages
• The Reduced Proper Motion selected halo: methods and description of the catalogue
• Optimal stellar photometry for multi-conjugate adaptive optics systems using science-based metrics
• Impact of distance determinations on Galactic structure. II. Old tracers
• Observational indicators of the transition from fully convective stars to stars with radiative cores
• Models for Metal-Poor Stars with Different Initial Abundances of C, N, O, Mg, and Si. III. Grids of Isochrones for $-2.5\le$ [Fe/H] $\le -0.5$ and Helium Abundances $Y=0.25$ and $0.29$ at Each Metallicity
• Stellar photometry with Multi Conjugate Adaptive Optics
• Some Old Globular Clusters (and Stars) Inferring That the Universe Is Older Than Commonly Accepted
• The GeMS/GSAOI Galactic Globular Cluster Survey (G4CS) II: Characterization of 47 Tuc with Bayesian Statistics
• Exploration about the origin of galactic and extragalactic star clusters through simulated H-R diagrams
• On the dwarf irregular galaxy NGC 6822. I. Young, intermediate and old stellar populations