case western reserve university



Clues on Galaxy Disk Evolution from Studies of `Superthin' Spirals

Lynn Matthews (Harvard/CfA)

`Superthins' are a subset of spiral galaxies seen edge-on that exhibit highly flattened stellar disks, unusually small disk scale heights, and little or no bulge component. These appear to be among the structurally simplest and dynamically least evolved disk galaxies observable in the local universe. Therefore studies of these objects can yield important insight into the manner in which both internal and external processes affect the evolution of galactic disks.

I will highlight some recent results from the analysis of multiwavelength observations of two nearby superthin spirals, with particular emphasis on sensitive new VLA HI imaging observations. One of these objects is extremely isolated, while the other is located in a group environment and in the process of undergoing a minor merger. I will discuss the clues these observations shed on a variety of phenomena governing the evolution of galaxy disks, including the origin of warps, disk stability, dynamical heating, and morphological transformations.