The Secular Evolution of M83 Central Bulge

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

Oxford, Reino Unido

Simposio; Formation and Evolution of Galaxy Bulges; 2007

International Astronomical Union

The luminosity profile of M83 bulge can be traced by ade Vaucouleurs' law between approx 200 pc and approx800 pc. The inner part can be fitted by a n=-1/2 Sersicprofile. Also the IR (J-K) color shows difference between theperiphery and the central part of the bulge, both propertiesindicating the presence of a pseudobulge. Previous Gemini-S 3-D,Pa beta  spectroscopy of the central approx 5'' x 13''revealed spider like diagrams indicating disk like motion aroundthree extended masses identified respectively with the opticalnucleus (ON), with the center of the bulge isophotes, similar to theCO kinematical center (KC), and with a condensation hidden atoptical wavelengths (HN), coincident with the largest lobe in10\,${\mu}$m emission, most probably a cannibalized satellite.Numerical simulations show that they suffer strong evaporation andthey would merge engulfing also the star forming arc in few hundredMyr, increasing the mass at the kinematical center by a factor ofive or more. Upper mass limit of putative Black Holes associated toON, KC and HN are a few ten thousand to a million solar masses.GMOS+Gemini imaging and spectroscopy of a chain of radio sources hasyield no optical high redshift counterparts. This radio sources arealigned with ON, neither associated to SN nor to HII regions andmight point to an older similar phenomenon, which left behind akick-off spur.