KINEMATICS OF THE CENTRAL REGIONS OF NGC 1672

摘要

We present the detailed velocity field of the central 2 kpc of tahe LINER galaxy NGC 1672. The isovelocity map show a rotational pattern with a velocity gradient of 50 km/s arcsec~-1 in the inner 6" (1 "≈ 70 pc), indicating a mass of ≈9 X 10~8 Mo iside a radius of 125 pc, equivalent to a density of ≈10~11Mo kpc~-3. It also shows some asymmetries on a larger scale. An offset of approximately equals 60 pc between the nuclear continuum barycentyer and the kinematical center is also found. Satoh's model fitting to the observed velocity field reveals several nonaxisymmetric residuals, which do not correlate well with the bar or the circumnuclear ring of H II regions. The inner rotation curve of NGC 1672 reveals that the circumnuclear ring of star formation is located on an inner Lindblad resonance (ILR), and not near the peak of the Lindblad curve, Ω -(k/2), as suggested by previous works, which also claimed that the ring rotates faster than its ambient. This motion is not confirmed by the two-dimensional residual-velocity map.