We present evidence for the existence of an old stellar halo in the Blue Compact Dwarf galaxy VII Zw 403 .
VII Zw 403 is the first Blue Compact Dwarf galaxy for which a clear spatial segregation of the resolved stellar content into a “ core-halo ” structure is detected .
Multicolor HST/WFPC2 observations indicate that active star formation occurs in the central region , but is strikingly absent at large radii .
Instead , a globular-cluster-like red giant branch suggests the presence of an old ( > 10 Gyr ) and metal poor ( < [ Fe/H ] > =-1.92 ) stellar population in the halo .
While the vast majority of Blue Compact Dwarf galaxies has been recognized to possess halos of red color in ground-based surface photometry , our observations of VII Zw 403 establish for the first time a direct correspondence between a red halo color and the presence of old , red giant stars .
If the halos of Blue Compact Dwarf galaxies are all home to such ancient stellar populations , then the fossil record conflicts with delayed-formation scenarios for dwarfs .