New age-metallicity diagnostic diagram for the Washington photometric system
arXiv:1504.03894 · doi:10.1093/mnras/stv861
Abstract
The age calibration of the Washington deltaT1 index is mainly used to estimate ages of star clusters older than 1 Gyr, no age-metallicity degeneracy effect is considered. We have profusely exploited synthetic T1 versus C-T1 colour magnitude diagrams aiming at exploring the intrinsic behaviour of the deltaT1 index. The analysis shows that deltaT1 varies with age and metal content as well. In general, the dependence on age weakens for ages greater than ~ 6 Gyr, and results even less sensitive to age as the metallicity decreases. For ages younger than ~ 5 Gyr deltaT1 shows a strong correlation with both age and metallicity. The deltaC index -defined as deltaT1 for the C passband- is also a combined measurement of age and metallicity. We introduce a new age-metallicity diagnostic diagram, deltaT1 versus deltaC - deltaT1, which has shown the ability of unambiguously providing age and metallicity estimates, simultaneously. The new procedure allows to derive ages from 1 up to 13 Gyr and metallicities [Fe/H] from -2.0 up to +0.5 dex, and is independent of the cluster reddening and distance modulus. It does solve the constraints found in the deltaT1 index and surpasses the performance of the standard giant branch metallicity method. All these features make the diagnostic diagram a powerful tool for estimating accurate ages as well as metallicities.
arXiv comment14 pages, 7 figures, accepted for publication in MNRAS
References in corpus (40)
- PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
- The Initial Mass Function of Stars: Evidence for Uniformity in Variable Systems
- Database of Geneva stellar evolution tracks and isochrones for UBVRIJHKLL'M, HST-WFPC2, Geneva and Washington photometric systems
- The Galactic disk mass-budget : I. stellar mass-function and density
- Synthetic Stellar Photometry - I. General considerations and new transformations for broad-band systems
- The age of the oldest Open Clusters
- Ca II Triplet Spectroscopy of Giants in SMC Star Clusters: Abundances, Velocities and the Age-Metallicity Relation
- Multiple stellar populations in Magellanic Clouds clusters. I. An ordinary feature for intermediate age globulars in the LMC?
- A Search for Old Star Clusters in the Large Magellanic Cloud
- ASteCA - Automated Stellar Cluster Analysis
- The star cluster formation history of the LMC
- On the metallicity of open clusters II. Spectroscopy
- The VMC Survey IV. The LMC star formation history and disk geometry from four VMC tiles
- Ages and Metallicities of Star Clusters and Surrounding Fields in the Outer Disk of the Large Magellanic Cloud
- The age-metallicity relationship of the Large Magellanic Cloud field star population from wide-field Washington photometry
- The Chemical Properties of Milky Way and M31 Globular Clusters: I. A Comparative Study
- Deriving star formation histories: Inverting HR diagrams through a variational calculus maximum likelihood method
- Constraining stellar population models - I. Age, metallicity, and abundance pattern compilation for Galactic globular clusters
- Washington photometry of candidate star clusters in the Small Magellanic Cloud
- The binary fractions in the massive young Large Magellanic Cloud star clusters NGC 1805 and NGC 1818
- Ages and metallicities of five intermediate-age star clusters projected towards the Small Magellanic Cloud
- Age and Mass for 920 LMC Clusters Derived from 100 Million Monte Carlo Simulations
- Standard Giant Branches in the Washington Photometric System
- Fitting Isochrones to Open Cluster photometric data: A new global optimization tool
- Helium in first and second-generation stars in Globular Clusters from spectroscopy of red giants
- Structural Parameters of Seven SMC Intermediate-Age and Old Star Clusters
- vbyCaHbeta CCD Photometry of Clusters. VIII. The Super-Metal Rich, Old Open Cluster NGC 6791
- From Young and Hot to Old and Cold: Comparing White Dwarf Cooling Theory to Main Sequence Stellar Evolution in Open Clusters
- Photometry of Magellanic Cloud clusters with the Advanced Camera for Surveys - II. The unique LMC cluster ESO 121-SC03
- Combined Effects of Binaries and Stellar Rotation on the Color-Magnitude Diagrams of Intermediate-Age Star Clusters
- New Clues to the Cause of Extended Main Sequence Turn-Offs in Intermediate-Age Star Clusters in the Magellanic Clouds
- On the Recovery of the Star Formation History of the LMC from the VISTA Survey of the Magellanic System
- Self-consistent physical parameters for five intermediate-age SMC stellar clusters from CMD modelling
- CCD photometry and membership segregation of the open cluster NGC2682 (M67)
- Toward the general RGB slope-metallicity-age calibration: I Metallicities, Ages and Kinematics for Eight LMC Clusters
- The star cluster frequency throughout the Large Magellanic Cloud
- The old, metal-poor, anticentre open cluster Trumpler 5
- Binary interactions as a possible scenario for the formation of multiple stellar populations in globular clusters
- No compelling evidence of significant early star cluster disruption in the Large Magellanic Cloud
- The Range of Variation of the Mass of the Most Massive Star in Stellar Clusters Derived from 35 Million Monte Carlo Simulations