Title: The Ying and Yang of M83's Core.

Authors: Ruben Diaz, Damian Mast, Horacio Dottori, Maria Aguero, Irapuan Rodrigues

Abstract: The spiral galaxy M83, an SB(rs)b located at only 4.5 Mpc, harbors the nearest starburst nucleus. Its proximity makes it a privileged case for mapping the detailed physics at spatial scales of tenth of parsecs, scales at which it shows a strong morphological complexity where dust and interactions play a main role. The study of this scenario would provide clues to the question of core growing and morphological evolution in grand-design spiral galaxies.
We now revisit the case with a much larger set (1500 spectra) of near-infrared 3D spectroscopy observations from Gemini-S, with a spatial resolution of 0.5 arcsec at J-band. The extended P_alpha velocity field confirms the presence of two dynamical centers with masses less than 10E7 M_sun, neither of them coincident with the bulge center.
The hidden nucleus is surrounded by dark young regions, and the optical nucleus is surrounded by luminous and relatively older complexes, in particular our numerical modeling suggest that the nuclei and bright clusters will merge in a single large core in a few tens of million years.
Adding complexity to this scenario, we also present Gemini-S optical imaging and spectroscopy of the radio source J133658.3-295105 located at the galaxy main body. The detected H_alpha emission at the position of this source, red-shifted by about 130 km/s with respect to an M83 HII region, leads us to face
the possibility of witnessing the ejection of an object by gravitational recoil from M83 core.