Kinematics of the central regions of NGC 1672

Abstract

We present the detailed velocity field of the central 2 kpc of the LINER galaxy NGC 1672. The iso- velocity map shows a rotational pattern with a velocity gradient of 50 km s-ˡ arcsec-ˡ in the inner 6" (1"≈ 70 pc), indicating a mass of ≈ 9x 108 Mʘ inside a radius of 125 pc, equivalent to a density of ≈ 2 x 1011 Mʘ kpc-³. It also shows some asymmetries on a larger scale. An o†set of ≈ 60 pc between the nuclear continuum barycenter and the kinematical center is also found. Satoh"s model Ðtting to the observed velocity Ðeld 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 conÐrmed by the two-dimensional residual- velocity map.