The Sombrero galaxy. III. Ionised gas and dust in the central 200 pc: a nuclear bar?

Abstract

We present the results of new 3D TIGER spectroscopic observations and archived HST/WFPC2 and NICMOS images of the central region of M 104. The [N ii]+Hα images reveal the presence of a nuclear spiral structure, and the gaseous kinematics in the central arcsecond shows evidence for kinematical decoupling of the central peak. A straight nuclear dust lane, with a weak symmetric counterpart, is seen in the V-I and V-H colour maps. These results hint for the presence of a strong nuclear bar, that would be located inside the inner Linblad resonance of the large-scale bar discussed by Emsellem (\cite{Ems95}). Based on observations taken with the Canada-France-Hawaii Telescope, operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique of France, and the University of Hawaii, and observations with the NASA/ESA Hubble Space telescope obtained at the Space Telescope European Coordinating Facility, jointly operated by ESA and the European Southern Observatory.}