Session 77 - Structures of Galaxies.
Display session, Friday, January 09
Exhibit Hall,

## [77.03] Modeling Lopsided Galactic Disks

S. E. Levine (USNO Flagstaff), L. S. Sparke (U. Wisconsin)

Many disk galaxies are lopsided: their brightest inner parts are displaced from the center of the outer isophotes, or the outer contours of the H\sc i disk. This asymmetry is particularly common in small, low-luminosity galaxies. We argue here that long-lived lopsidedness is a consequence of the disk lying off-center in the potential of the galaxy's extended dark halo, and spinning in a sense retrograde to its orbit about the halo center. The predicted stellar velocity field is clearly asymmetric.