The secular evolution of M83 central bulge

DOTTORI, HORACIO; DÍAZ, R.; AGUERO, MARIA P.; MAST, D.; RODRIGUES, IRAPUAN

Oxford

Simposio; Formation and Evolution of Galaxy Bulges - IAU Symposium No. 245; 2007

Oxford University

The luminosity profile of M 83 bulge can be traced by a de Vaucouleurs´ law between approx 200 pc and approx 800 pc. The inner part can be fitted by a n = -1/2 Sérsic profile. Also the IR (J - K) color shows difference between the periphery and the central part of the bulge, both properties indicating the presence of a pseudobulge. Previous Gemini-S 3-D, Pa_beta spectroscopy of the central approx 5''×13'' revealed spider like diagrams indicating disk like motion around three extended masses identified respectively with the optical nucleus (ON), with the center of the bulge isophotes, similar to the CO kinematical center (KC), and with a condensation hidden at optical wavelengths (HN), coincident with the largest lobe in 10 μm emission, most probably a cannibalized satellite. Numerical simulations show that they suffer strong evaporation and they would merge engulfing also the star forming arc in few hundred Myr, increasing the mass at the kinematical center by a factor o five or more. Upper mass limit of putative Black Holes associated to ON, KC and HN are a few ten thousand to a million solar masses. GMOS+Gemini imaging and spectroscopy of a chain of radio sources has yield no optical high redshift counterparts. This radio sources are aligned with ON, neither associated to SN nor to HII regions and might point to an older similar phenomenon, which left behind a kick-off spur.