Bibcode
Knapen, J. H.; Sharp, R. G.; Ryder, S. D.; Falcón-Barroso, J.; Fathi, K.; Gutiérrez, L.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 408, Issue 2, pp. 797-811.
Advertised on:
10
2010
Citations
30
Refereed citations
26
Description
We report new near-IR integral field spectroscopy of the central
starburst region of the barred spiral galaxy M83 obtained with Cambridge
Infra-Red Panoramic Survey Spectrograph (CIRPASS) on Gemini-South, which
we analyse in conjunction with GHαFaS Fabry-Perot data, an
Anglo-Australian Telescope (AAT) IRIS2 Ks-band image, and
near- and mid-IR imaging from the Hubble and Spitzer space telescopes.
The bulk of the current star formation activity is hidden from optical
view by dust extinction, but is seen in the near- and mid-IR to the
north of the nucleus. This region is being fed by inflow of gas through
the bar of M83, traced by the prominent dust lane entering into the
circumnuclear region from the north. An analysis of stellar ages
confirms that the youngest stars are indeed in the north-west. A gradual
age gradient, with older stars further to the south, characterizes the
well-known star-forming arc in the central region of M83, and is
consistent with a stable scenario where gas inflow into the central
regions is facilitated by the galactic bar.
Detailed analyses of the Paβ ionized gas kinematics and near-IR
imaging confirm that the kinematic centre coincides with the photometric
centre of M83, and that these are offset significantly, by about 3arcsec
or 60pc, from the visible nucleus of the galaxy. We discuss two possible
options, the first of which postulates that the kinematic and
photometric centre traces a galaxy nucleus hidden by a substantial
amount of dust extinction, in the range AV = 3-10mag. By
combining this information with kinematic results and using arguments
from the literature, we conclude that such a scenario is, however,
unlikely, as is the existence of other `hidden' nuclei in M83.
We thus concur with recent authors and favour a second option, in which
the nucleus of the galaxy is offset from its kinematic and photometric
centre. This is presumably a result of some past interaction, possibly
related to the event which lies at the origin of the disturbance of the
outer disc of the galaxy. We find some indications for a disturbance in
the Hα velocity field which would confirm the influence of the m =
1 perturbation in the gravitational potential, but note that further
high-quality stellar kinematic data are needed to confirm this scenario.
Related projects
Spiral Galaxies: Evolution and Consequences
Our small group is well known and respected internationally for our innovative and important work on various aspects of the structure and evolution of nearby spiral galaxies. We primarily use observations at various wavelengths, exploiting synergies that allow us to answer the most pertinent questions relating to what the main properties of
Johan Hendrik
Knapen Koelstra