A study is presented of the central structure and kinematics of the galaxy
NGC 6951, by means of broad band B'IJK images and high resolution high
dispersion longslit spectroscopy, together with archival HST WFPC2 V and
NICMOS2 J and H images. We find that there is evidence of two modes of star
formation, in bursts and continuously. The equivalent width of the CaII triplet
absorption lines show that, in the metal rich central region, the continuum is
dominated by a population of red supergiants. The gaseous and stellar
kinematics along three slit position angles, suggest the existence of a
hierarchy of disks within disks, whose dynamics are decoupled at the two ILRs,
that we find at 180 pc and at 1100 pc. This is supported by the structure seen
in the high resolution HST images. The nucleus is spatially resolved within a
radius of 1.5 arcsec, just inside the innermost ILR. Outside the iILR, the
stellar CaT velocity profile is resolved into two components, associated with
the bar and the disk. Several results indicate that this is a dynamically old
system. It is thus possible that a nuclear bar has existed in NGC 6951 that
drove the gas towards the nucleus, as in the bars within bars scenario, but
that this bar has already dissolved by the gas accumulated within the
circumnuclear region. We discuss the possibility that the kinematical component
inside the iILR could be due to a nuclear outflow produced by the combined
effects of SN and SN remnants, or to a nuclear disk, as in the disk within disk
scenario that we propose for the fueling of the AGN in NGC 6951.Comment: 14 pages, 16 figures. Accepted for publication in Astronomy and
Astrophysics. High resolution images in
http://www.iaa.es/~eperez/research/degas.htm
