Star clusters in the dwarf irregular galaxy Leo A
  Leo A is an isolated gas-rich dwarf irregular galaxy of low stellar mass and
metallicity residing at the outskirts of the Local Group. Ages of the stellar
populations in Leo A range from $\sim$10 Myr to $\sim$10 Gyr. So far, only one
star cluster has been discovered in this galaxy. Our aim is to search for star
cluster candidates in the Leo A galaxy. We performed photometry of star-like
objects on HST ACS archive observation frames in the $F475W$ and $F814W$
passbands and studied the spatial clustering of the Leo A stars down to the
turn-off point of the old stellar populations. We report the discovery of four
star clusters in the Leo A galaxy. This means that now a sample of five star
clusters is known in Leo A. Two clusters are of a young age ($\sim$20 Myr;
overlapping with HII regions) and low in mass ($\gtrsim$400 M$_\odot$ and
$\gtrsim$150 M$_\odot$), the other three clusters are older ($\gtrsim$100 Myr)
and also of low mass ($\gtrsim$300 M$_\odot$). These rough estimates are made
assuming the isochrones of a metallicity derived for HII regions ($Z=0.0007$).
Colour-magnitude diagrams of the stars residing in the circular areas of a
2.5arcsec radius around the clusters and integrated aperture photometry results
of the clusters are presented.
