We present a new method to derive 2D star formation histories in dwarf irregular galaxies. Based on multicolor stellar photometry data we have found that in the Leo A galaxy during the last ∽400 Myr star formation was propagating according to the inside-out scenario. Star-forming regions have spread strongly asymmetrically from the center and their present day distribution correlates well with the Hi surface density maps.

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 & 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 ~200 Myr. Also, we have discovered 5 low-mass (≲ 400 M⊙) 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 H i 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).