Astrophysical properties of star clusters in the Magellanic Clouds homogeneously estimated by ASteCA

Abstract

Aims. We seek to produce a homogeneous catalog of astrophysical parameters of 239 resolved star clusters, located in the Small and Large Magellanic Clouds, observed in the Washington photometric system. Methods. The cluster sample was processed with the recently introduced Automated Stellar Cluster Analysis (ASteCA) package, which ensures both an automatized and a fully reproducible treatment, together with a statistically based analysis of their fundamental parameters and associated uncertainties. The fundamental parameters determined for each cluster with this tool, via a color-magnitude diagram (CMD) analysis, are metallicity, age, reddening, distance modulus, and total mass. Results. We generated a homogeneous catalog of structural and fundamental parameters for the studied cluster sample and performed a detailed internal error analysis along with a thorough comparison with values taken from 26 published articles. We studied the distribution of cluster fundamental parameters in both Clouds and obtained their age-metallicity relationships. Conclusions. The ASteCA package can be applied to an unsupervised determination of fundamental cluster parameters, which is a task of increasing relevance as more data becomes available through upcoming surveys.

The period-age relation of long-period variables

“…As discussed by Kamath et al (2010), the age of the SMC cluster NGC 419 is believed to be around 1.4-1.6 Gyr. This is consistent with the value τ = 1.45 ± 0.05 Gyr from Goudfrooij et al (2014), while it is as young as τ 0.89 ± 0.015 Gyr according to Perren et al (2017). Since an accurate estimate is not necessary for our exploratory analysis, we took a rough average and assumed log(τ/yr) = 9.1 ± 0.1.…”

“…Distances of Galactic clusters were also taken from Kharchenko et al (2016), while for the Magellanic Clouds and their clusters we adopted the distance moduli µ LMC = 18.49 ± 0.09 mag and µ SMC = 18.96 ± 0.02 mag from de Grijs et al (2017). We searched for data on interstellar extinction from several literature works (e.g., Nayak et al 2016;Kharchenko et al 2016;Perren et al 2017), all of which suggest that extinction in the K s filter is smaller than ∼0.1 mag for most of the clusters we considered, and at most as large as ∼0.3 mag, which is negligible for our purposes.…”

Stellar wind retention and expulsion in massive star clusters

“…More locally, the effects of gas retention on observations of SMC and LMC star clusters has focused predominately on the YMC population (Bastian & Strader 2014;Longmore 2015). While there are IACs in the LMC and SMC with large extinctions there is not an overall trend with age (Perren et al 2017) as would be suggested by the work presented here. However, we caution here that once again LMC and SMC clusters are not necessarily the isolated systems discussed in this work.…”

Sixteen overlooked open clusters in the fourth Galactic quadrant

“…We shall limit ourselves to give a brief summary about the way the positional and photometric data are employed by the code. A complete description of Perren et al (2015) and Perren et al (2017). The basic hypothesis of any stellar cluster analysis is that the region occupied by a real cluster and the surrounding field should show "a priori" different properties.…”