Ages of LMC Star Clusters using ASAD${}_2$

Abstract

We use ASAD${}_2$, the new version of ASAD (Analyzer of Spectra for Age Determination), to obtain the age and reddening of 27 LMC clusters from full fitting of integrated spectra using different statistical methods (${\chi }^2$ and K-S test) and a set of stellar population models including GALAXEV and MILES. We show that our results are in good agreement with the CMD ages for both models, and that metallicity does not affect the age determination for the full spectrum fitting method regardless of the model used for ages with log (age/year) $<$ 9. We discuss the results obtained by the two statistical results for both GALAXEV and MILES versus three factors: age, S/N and resolution (FWHM). The predicted reddening values when using the ${\chi }^2$ minimization method are within the range found in the literature for resolved clusters (i.e: $<$ 0.35), however the K-S test can predict E(B$-$V) higher values. The sharp spectrum transition originated at ages around the supergiants contribution, at either side of the AGB peak around log (age/year) 9.0 and log (age/year) 7.8 are limiting our ability to provide values in agreement with the CMD estimates and as a result the reddening determination is not accurate. We provide the detailed results of four clusters spanning a wide range of ages. ASAD${}_2$ is a user-friendly program available for download on the Web and can be immediately used at $http://randaasad.wordpress.com/asad-package/$.

Accepted for publication in MNRAS

References in corpus (4)

• Evolutionary Stellar Population Synthesis with MILES. Part I: The Base Models and a New Line Index System
• Evolutionary stellar population synthesis with MILES - II. Scaled-solar and α-enhanced models
• Physical parameters of 15 intermediate-age LMC clusters from modelling of HST colour-magnitude diagrams
• Analyzer of Spectra for Age Determination (ASAD) - Algorithm and Applications

Cited by in corpus (10)

• Young LMC clusters: the role of red supergiants and multiple stellar populations in their integrated light and CMDs
• Using Star Clusters as Tracers of Star Formation and Chemical Evolution: the Chemical Enrichment History of the Large Magellanic Cloud
• Metallicity estimates of young clusters in the Magellanic Clouds from Stromgren photometry of supergiant stars
• A novel method to automatically detect and measure the ages of star clusters in nearby galaxies: Application to the Large Magellanic Cloud
• On the Precision of Full-spectrum Fitting of Simple Stellar Populations. I. Well-sampled Populations
• On the precision of full-spectrum fitting of simple stellar populations. II. The dependence on star cluster mass in the wavelength range 0.3-5.0 $\mu$m
• Detailed Chemical Abundances of Star Clusters in the Large Magellanic Cloud
• On the Precision of Full-spectrum Fitting of Stellar Populations. III. Identifying Age Spreads
• On the Precision of Full-Spectrum Fitting of Simple Stellar Populations. IV. A Systematic Comparison with Results from Colour-Magnitude Diagrams
• Ages and metallicities of stellar clusters using S-PLUS narrow-band integrated photometry: the Small Magellanic Cloud