Quantitative Morphology at High Redshifts

Abstract

The current evidence for morphologically peculiar galaxy populations at high-redshifts is outlined. After describing various techniques which can be used to quantify the importance of ``morphological K-corrections'', and to objectively classify galaxy morphology in the presence of these biases, it is concluded that observational biases are not sufficient to explain the increase in the fraction of peculiar galaxies on deep HST images. A new technique is then described which models the spatially resolved internal colors of high redshift galaxies, as a probe of the processes driving galaxy evolution. This ``morphophotometric'' approach investigates directly the evolutionary history of stellar populations, and is a sensitive test of the mechanisms through which galaxies build up and evolve in the field. As a case study, we analyse several ``chain galaxies'' in the Hubble Deep Field. These chain galaxies are shown to be protogalaxies undergoing their first significant episodes of star-formation, and not simply distant edge-on spirals.