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P. Moth, R.J. Elston (UF)
We have searched for color gradients in the optical rest-frame colors for a large sample of high redshift galaxies in the Hubble Deep Field (HDF). We fit elliptical isophotes to WFPC-2 IF814W and NICMOS JF110W and HF160W images of the HDF. From the HDF images, we can probe to fainter surface brightness limits and smaller angular scales than before, the sizes, shapes, and colors of distant galaxies. Our preliminary observations of the (IF814W-JF110W) color gradients in a number of galaxies with 2.0 < z < 3.0 indicate significant color changes. These observations point to bluer colors towards the center and imply that star formation is centrally condensed in these galaxies. To each surface brightness profile, we fit an exponential disk model to isolate compact starburst regions from any underlying older and diffuse component. In general, we find that the exponential models fit the surface brightness profiles of galaxies in this redshift range well, indicating that these galaxies have profiles similar to disks with no evidence of a spheroidal component. With further analysis, we will determine whether color changes and disky structures are predominant in high redshift galaxies and discuss implications for galaxy formation and evolution.
The author(s) of this abstract have provided an email address for comments about the abstract: pimol@astro.ufl.edu