Palomar/Las Campanas Imaging Atlas of Blue Compact Dwarf Galaxies. II. Surface Photometry and the Properties of the Underlying Stellar Population

We present the results from an analysis of surface photometry of B, R, andHalpha images of a total of 114 nearby galaxies drawn from the Palomar/LasCampanas Imaging Atlas of Blue Compact Dwarf galaxies. Surface brightness andcolor profiles for the complete sample have been obtained. We determine theexponential and Sersic profiles that best fit the surface brightnessdistribution of the underlying stellar population detected in these galaxies.We also compute the (B-R) color and total absolute magnitude of the underlyingstellar population and compared them to the integrated properties of thegalaxies in the sample. Our analysis shows that the (B-R) color of theunderlying population is systematically redder than the integrated color,except in those galaxies where the integrated colors are strongly contaminatedby line and nebular-continuum emission. We also find that galaxies withrelatively red underlying stellar populations (typically (B-R)>~1mag) showstructural properties compatible with those of dwarf elliptical galaxies (i.e.a smooth light distribution, fainter extrapolated central surface brightnessand larger scale lengths than BCD galaxies with blue underlying stellarpopulations). At least ~15% of the galaxies in the sample are compatible withbeing dwarf elliptical (dE) galaxies experiencing a burst of star formation.For the remaining BCD galaxies in the sample we do not find any correlationbetween the recent star formation activity and their structural differenceswith respect to other types of dwarf galaxies.