3D NIR spectroscopy of M 83 central region with subarcsecond resolution


Diaz Ruben, Dottori Horacio, Aguero Maria, Mediavilla Evencio, Mast Damian


We report the status of our study of the central region of M 83. Recently a binary mass concentration at the nucleus was suggested by Thatte et al. (2000), and we determined the possible position of the hidden secondary mass concentration with 2D H-alpha kinematics. We continue our study of this region trough 3D NIR spectroscopy performed with CIRPASS, attached to the Gemini South telescope. Almost 1500 spectra were obtained, centered in the wavelength 1.3 microns. They allow us to resolve, with 0.36 arcsecond (6.4 pc) sampling and subarcsecond resolution, the velocity field in a region of 13 x 9 arcseconds around the optical nucleus. We confirm that the optical nucleus is not located at the most important center of symmetry of the ionized gas velocity field. The largest black hole that could fit to the circular motion in this kinematic center should have a mass lower than 2E7 solar masses.