Gemini 3D infrared spectroscopy: Double nucleus in M 83

Abstract

Abstract. 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 optically hidden mass concentration with 2D Hα kinematics. We continue our study of this region trough IR 3D spectroscopy performed with CIRPASS, attached to the Gemini South telescope. Almost 1500 spectra were obtained, centered in the wavelength 1.3 µm. The velocity field in a region of 13" × 9" around the optical nucleus is resolved, with 0.36" (6.4 pc) sampling. We confirm that the optical nucleus of M 83 is not located at the most important center of symmetry of the velocity field. The largest black hole that could fit to the circular motion in this kinematic center should have a mass less than 2 × 10 7 M .