The Many Vortexs of NGC 5236 Nucleus in the Central 80x200 Parsecs

DIAZ, R.; MAST, D.; AGUERO, M. P.; RODRIGUES, I.; DOTTORI, H.

Prague, Czech Republic

Simposio; Galaxy Evolution Across the Hubble Time; 2006

International Astronomical Union

GEMINI-S+CIRPASS configuration has been used to obtain 1500 spectra of high quality, centred in 1.3 microns of the NW-SE oriented, central 80x200 pc of M83, with a spectral resolving power of 3200. We determine the kinematics of this region with 0.36 arcsec sampling and sub-arcsec resolution. Disk-like motions are detected in Pbeta at parsecs scales around: (a) the optical nucleus, (b) the dynamical centre of the CO velocity map (Sakamoto et al. 2004) coincident with the centre of the external isophotes (Thatte et al, 2003), and located 50 pc to the W of the optical nucleus as well as (c) the hidden condensation (Mast et al 2006), now more precisely located at 120 pc to the N-NW of the optical nucleus . Furthermore, with the present resolution another whirl is detected near the position of the blue-shifted lobe of the hidden condensation, coincident with a bright knot in the HST image. The disk around (a) has a radius of around 10-15 pc and the two around (b) and (c) can be traced approximately up to 40-50 pc from their kinematical centres. The rotation curve can be fitted by Satoh like spheroids indicating masses of 2-4 E6 Msun, 10-15 E6 Msun and 15-20 E6 Msun respectively. N-body simulations show that nuclei (a), (b) and (c) will merge in 10-50 Myrs. A question that arise immediately is if this degree of dynamical activity is peculiar of M83 or it is seen in this galaxy in all its dramaticity due to its small distance from us.