M/L, Hα Rotation Curves, and HiGas Measurements for 329 Nearby Cluster and Field Spirals. III. Evolution in Fundamental Galaxy Parameters

We have conducted a study of optical and HI properties of spiral galaxies(size, luminosity, H-alpha flux distribution, circular velocity, HI gas mass)to investigate causes (e.g., nature versus nurture) for variation within thecluster environment. We find HI deficient cluster galaxies to be offset inFundamental Plane space, with disk scale lengths decreased by a factor of 25%.This may be a relic of early galaxy formation, caused by the disk coalescingout of a smaller, denser halo (e.g., higher concentration index) or bytruncation of the hot gas envelope due to the enhanced local density ofneighbors, though we cannot completely rule out the effect of the gas strippingprocess. The spatial extent of H-alpha flux and the B-band radius alsodecreases, but only in early type spirals, suggesting that gas removal is lessefficient within steeper potential wells (or that stripped late type spiralsare quickly rendered unrecognizable). We find no significant trend in stellarmass-to-light ratios or circular velocities with HI gas content, morphologicaltype, or clustercentric radius, for star forming spiral galaxies throughout theclusters. These data support the findings of a companion paper that gasstripping promotes a rapid truncation of star formation across the disk, andcould be interpreted as weak support for dark matter domination over baryons inthe inner regions of spiral galaxies.Comment: 12 pages, 7 figures; accepted for publication in A