Mass estimates for Small Magellanic Cloud clusters from Washington photometry

F.F.S. MAIA; A.E. PIATTI; J.F.C.SANTOS

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2014 vol. 437 p. 2005 - 2016

0035-8711

     In this work we estimate, for the first time, the total masses and mass function slopes of asample of 29 young and intermediate-age SMC clusters from CCD Washington photometry.We also derive age, interstellar reddening and structural parameters for most of the studiedclusters by employing a statistical method to remove the unavoidable field star contamination.Only these 29 clusters out of 68 originally analysed cluster candidates present stellar over-densities and coherent distribution in their colour-magnitude diagrams compatible with theexistence of a genuine star cluster. We employed simple stellar population models to derivegeneral equations for estimating the cluster mass based only on its age and integrated light inthe B, V , I, C and T1 filter. These equations were tested against mass values computed fromluminosity functions, showing an excellent agreement. The sample contains clusters with agesbetween 60 Myr and 3 Gyr and masses between 300 and 3000 M⊙ distributed between ∼0.5◦and ∼2◦ from the SMC optical centre. We determined mass function slopes for 24 clus-ters, of which 19 have slopes compatible with that of Kroupa?s IMF (α = 2.3 ± 0.7),considering the uncertainties. The remaining clusters ? H86-188, H86-190, K47, K63and NGC242 ? showed flatter MFs. Additionally, only clusters with masses inferior to∼1000 M⊙ and flatter MF were found within 0.6 deg. from the SMC rotational centre.