The Effect of Environment on Mass and Light in Spiral Galaxies
Session 98 -- Galaxies and Cluster Environment
Oral presentation, Friday, January 14, 2:15-3:45, Salon V Room (Crystal Gateway)

## [98.04] The Effect of Environment on Mass and Light in Spiral Galaxies

N. P. Vogt (Cornell)

A survey of 290 nearby galaxies (z $<$ 0.04) has been conducted to resolve the conflicting results of previous studies concerning the distribution of mass and light of galaxies within differing cluster environments. Mass models are fit to combined H$\alpha$ and [NII] rotation curves, and I--band images deconvolved into disk and bulge components for comparison. HI line profiles provide an equivalent velocity width measurement, and serve as a valuable measure of HI deficiency, particularly for gas-poor objects in cluster cores. The gradient of the velocity profile and terminal velocity point are evaluated relative to the limiting surface brightness of the galaxy image and as a function of disk scale length, and a search is made for variations which correlate with HI deficiencies. A comparison of galaxies within and beyond the Abell radius provides information on the dependence on cluster density.

The data set consists of 260 high quality optical rotation curves in 11 Abell clusters (15 - 25 galaxies per cluster), with an additional 30 field galaxies at comparable distances, all obtained using the Double Spectrograph on the Palomar 5--meter telescope. HI line data has been acquired for all galaxies in the sample observable from Arecibo Observatory, and I--band images have been taken with the KPNO 0.9--meter or the MDM 1.3--meter telescope for the complete sample. A representative sample of the study is presented and an initial analysis of the data is discussed.