Detalles de publicación
PP 010041
The central region of M83: Massive star formation, kinematics, and the location and origin of the nucleus
(1) Instituto de Astrofisica de Canarias, E-38200 La Laguna, Tenerife, Spain
(2) Departamento de Astrofisica, Universidad de La Laguna, E-38205 La
Laguna, Tenerife, Spain
(3) Anglo-Australian Observatory, PO Box 296, Epping, NSW 1710, Australia
(4) European Space Research & Technology Centre, Keplerlaan 1,
Postbus 299, 2200 AG Noordwijk, The Netherlands
(5) Stockholm Observatory, Department of Astronomy, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden
(6) Oskar Klein Centre for Cosmoparticle Physics, Stockholm University,
SE-106 91 Stockholm, Sweden
(7)Universidad Nacional Autonoma de Mexico, Apartado
Postal 877, Ensenada, B.C. 22800, Mexico}
We report new near-IR integral field spectroscopy of the central
starburst region of the barred spiral galaxy M83 obtained with CIRPASS on Gemini-S, which we analyse in conjunction with G\ha FaS Fabry-Perot data, an AAT IRIS2 $K_{\rm s}$-band image, and near- and mid-IR imaging from the {\it Hubble} and {\it 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 northwest. A gradual age gradient, with older stars further to the south, characterises 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
\pab\ ionised 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 3\,arcsec or 60\,pc, 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 $A_V=3-10$\,mag. 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 disk of the galaxy. We find some indications for a disturbance in the \ha\ 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.
starburst region of the barred spiral galaxy M83 obtained with CIRPASS on Gemini-S, which we analyse in conjunction with G\ha FaS Fabry-Perot data, an AAT IRIS2 $K_{\rm s}$-band image, and near- and mid-IR imaging from the {\it Hubble} and {\it 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 northwest. A gradual age gradient, with older stars further to the south, characterises 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
\pab\ ionised 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 3\,arcsec or 60\,pc, 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 $A_V=3-10$\,mag. 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 disk of the galaxy. We find some indications for a disturbance in the \ha\ 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.