AAS Meeting #193 - Austin, Texas, January 1999
Session 3. Galaxy Evolution and Surveys II - High Redshift
Display, Wednesday, January 6, 1999, 9:20am-6:30pm, Exhibit Hall 1

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[3.01] Morphological Peculiarity Indices of Local and Distant Galaxies

K. L. Wu (UCSC), S. M. Faber (UCO/Lick), T. R. Lauer (KPNO/NOAO)

Detailed images from the Hubble Space Telescope (HST) have sparked a surge of interest in morphological peculiarities in both distant and local galaxies. Several groups have developed criteria by which to automatically classify galaxy morphology (e.g., Abraham et al. 1996, Naim et al. 1997).

In order to study peculiar galaxies at high redshifts, it is crucial to have a solid understanding of both the morphological peculiarities in local galaxies and the appearance of these features when observed at higher redshifts.

We are developing several algorithms, or peculiarity indices, to quantify the types and degree of peculiarity seen in galaxy morphology. It is not our aim to classify galaxies on the ``normal'' Hubble Sequence. The focus of this work is an asymmetry index, which is a variation of that presented by Abraham et al. 1996.

The indices are applied initially to two samples: (1) a local galaxy sample, comprised of the Frei, et al. 1996 ``Catalog of Nearby Galaxies,'' along with several merger candidates from two runs on the Lick Observatory Nickel 40-inch telescope by one of the authors (KLW); and (2) simulations of the above sample of galaxies cosmologically shifted to z ~0.8.

This study expands upon previous work by providing a realistic view of which local morphological features we can expect to measure robustly when observed at high redshifts with the current observational technology.

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