Star formation history of KDG 61 and KDG 64 from spectroscopy and
  colour-magnitude diagrams
  A study of two dE/dSph members of the nearby M 81 group of galaxies, KDG 61
and UGC 5442 = KDG 64, has been made. Direct Hubble Space Telescope (HST)
Advanced Camera for Surveys (ACS) images and integrated-light spectra of 6 m
telescope of Special Astrophysical Observatory of Russian Academy of Sciences
have been used for quantitative star formation history analysis. The
spectroscopic and colour-magnitude diagrams analysis gives consistent results.
These galaxies appear to be dominated by an old population (12-14 Gyr) of low
metallicity ([Fe/H]~-1.5). Stars of ages about 1 to 4 Gyr have been detected in
both galaxies. The later population shows marginal metal enrichment. We do not
detect any significant radial gradients in age or metallicity in these
galaxies. Our radial velocity measurement suggests that the HII knot on the
line-of-sight of KDG 61 is not gravitationally attached to the galaxy.
