Using the high-resolution capability of HST we examine the morphological properties of galaxies observed from 20 Wide Field Camera (WFC) fields as a function of broad-band colors. Ground-based BVR photometry is used to extend the color-baseline of the F555W (V) and F785LP (I) passbands obtained with HST. The galaxy sample contains only field galaxies and is essentially complete down to 24.5(23) mag in V(I) for deep multi-orbit exposures, with a corresponding limit ~ 1 mag brighter for single-orbit exposures. The median redshift for galaxies imaged in multi-orbit frames is z ~ 0.3--0.5. WFC images are presented for the brighter galaxies of our sample and galaxy scale lengths are given for the complete galaxy sample as a function of apparent magnitude and broad-band colors. With this data we consider the fraction of galaxies with disturbed morphologies both in blue- and red-selected samples. Further, we identify the galaxies as bulge- or disk-dominated using a profile fitting algorithm which accounts for the effects of the position-varying HST point spread function. This information is used to estimate the agreement with no-evolution predictions in color-magnitude and color-color diagrams. This work was supported by NASA/HST grants GO-2684-0X-87A and GO-3917-0X-91A from STScI, which is operated by AURA, Inc., under NASA contract NAS5-26555.
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 1993