Paper detail

Star clusters and young populations in the dwarf irregular galaxy Leo A

We have studied young stellar populations and star clusters in the dwarf irregular galaxy Leo A using multicolor ($B$, $V$, $R$, $I$, $Hα$) photometry data obtained with the Subaru Suprime-Cam and two-color photometry results measured on archival HST/ACS $F475W$ and $F814W$ frames. The analysis of the main sequence (MS) and blue supergiant (BSG - "blue loop") stars enabled us to study the star formation history in the Leo A galaxy during the last $\sim$200 Myr. Also, we have discovered 5 low-mass ($\lesssim$400 M$_\odot$) star clusters within the ACS field. This finding, taking into account a low metallicity environment and a yet-undetected molecular gas in Leo A, constrains star formation efficiency estimates and scenarios. Inside the well known "hole" in the HI column density map (Hunter et al. 2012) we found a shock front (prominent in $Hα$), implying an unseen progenitor and reminding the "hole" problems widely discussed by Warren et al. (2011).