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E. J. Murphy, W. H. Waller (Tufts University), J. D. P. Kenney (Yale University)
We present integrated-field spectroscopy and derived kinematics of the central kpc in the ringed-barred galaxies NGC~3351 and NGC~4736. The SB(r)b II galaxy NGC~3351 (M95) is a classic "theta" type ringed-barred system, whereas the (R)SA(r)ab II galaxy NGC~4736 (M94) is not strongly barred, but instead contains an oval-shaped disk, an unusually bright inner ring, and a nuclear mini-bar. Core data covering a 45" x 30" region in each galaxy was collected at the WIYN 3.5-m telescope using the Densepak multifiber array and Bench spectrograph. Using cross correlation techniques involving template star spectra, we have derived maps of radial velocity and velocity dispersion in each galaxy core. The resulting stellar velocity fields are remarkably regular in both galaxies, with contours indicative of pure rotation. The rotation rates are significantly lower than those derived from CO measurements (30-55 km/s lower in NGC~3351 and 20-35 km/s lower in NGC~4736) due to a combination of non-circular gas motions and dynamically significant random stellar motions. Kinematic comparisions with other spiral galaxies are considered with the aim of determining the respective roles of disks, bars, and bulges in spiral galaxy cores.
The author(s) of this abstract have provided an email address for comments about the abstract: emurph02@tufts.edu