Star Formation History of KDG 61 and KDG 64 From Spectroscopy and Colour-Magnitude Diagrams

Makarova, L.; Koleva, M.; Makarov, D.; Prugniel, Ph.
Bibliographical reference

EAS Publications Series, Volume 48, 2011, pp.65-66

Advertised on:
7
2011
Number of authors
4
IAC number of authors
1
Citations
0
Refereed citations
0
Description
We present a study of two dE/dSph members of the nearby M 81 group of galaxies, KDG 61 and KDG 64. Direct HST/ACS images and integrated-light spectra of 6 m telescope of Special Astrophysical Observatory (Russia) 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. Our radial velocity measurement suggests that the HII knot on the line-of-sight of KDG 61 is not gravitationally attached to the galaxy.