Spatially resolved study of the Local Group galaxies
  We have been investigating the metallicity dependence of star and planet
formation, particularly focusing on the outer Galaxy with a Galactocentric
distance ($R_g$) of $\gtrsim$15 kpc, where the metallicity is determined to be
as low as $\sim$$-$1 dex. We have obtained near-infrared (NIR) images of young
clusters in the outer Galaxy through the 8.2-m Subaru Telescope and have
clearly resolved the cluster members with mass detection limits of $\sim$0.1
$M_\odot$. Consequently, we determined that the initial mass function (IMF) in
the outer Galaxy is consistent with that in the solar neighborhood with regard
to high-mass slope and IMF peak. Meanwhile, we suggested that the lifetime of
protoplanetary disks is significantly shorter than that in the solar
neighborhood. We also reported a metallicity dependence of the disk lifetime.
Future observations with higher spatial resolution and sensitivity by using ELT
will allow us to extend the spatially resolved studies on the IMF and
protoplanetary disk evolution to Local Group galaxies. With high spatial
resolution and sensitivity (i.e. 0.02 arcsec and $K\sim27$ mag with an adaptive
optics), stars with mass of down to $\sim$0.1 $M_\odot$ can be detected and
also sufficiently resolved. Based on such a study in a wider variety of
environments, we can gain new insights related to environmental effects of star
and planet formation.
