Astronomy and Astrophysics, volume 314, 59-72 (1996/10-1)
Optical structure and star formation in blue compact dwarf galaxies. II. Relations between photometric components and evolutionary implications.
PAPADEROS P., LOOSE H.-H., FRICKE K.J. and THUAN T.X.
Abstract (from CDS):
In a preceding paper, we have derived the structural parameters of the young high-surface-brightness stellar component formed in starbursts and that of the old underlying low-surface-brightness component, by applying a 3-component decomposition scheme to the surface brightness profiles of 12 blue compact dwarf galaxies (BCDs) and 2 starburst galaxies. Here we compare the various properties of these two components. We find that the size of the starburst component depends on the size and luminosity of the underlying component, as well as on the HI mass of the BCD. Furthermore, the fractional surface occupied by the star-forming regions decreases with increasing luminosity of the underlying host galaxy. We compare the structural properties of BCDs with those of other types of dwarf galaxies. We find that, at equal B luminosity, the underlying component of a BCD has a central surface brightness brighter by ∼1.5 mag and an exponential scale length smaller by a factor of ∼2 than that of dwarf irregulars (dIs) and dwarf ellipticals (dEs). Thus there can be evolutionary connections between BCDs and dEs and dIs only if the BCD underlying component can modify its structural properties. This may occur in response to changes in the global gravitational potential of the dwarf galaxy, caused by such events as mass infall from the outer gas halo and/or mass loss in starburst-driven galactic winds.