Luminous Infrared Galaxies. II. NGC 4945: A Nearby Obscured Starburst/Seyfert Nucleus

We have studied the physical conditions, reddening, and kinematics in the nuclear and circumnuclear regions of the luminous IR source NGC 4945. The I-band image shows a wide cone of radiation that emerges from the partially obscured nuclear region. The Hα + [N II] image reveals an extended nuclear region located at the same position as the I-band nucleus. Two extended filaments emerge from this region as well. Aperture optical spectroscopy of the nuclear region shows strong reddening in the continuum, and only the blends Hα + [N II] and [S II] appear in emission. The long-slit spectroscopy at P.A. = 90°, coincident with the main Hα filament, shows in the nuclear region a weak [O I] LINER or weak [O III] Seyfert spectrum and blueshifted broad components in the [N II] and [S II] lines that are probably associated with superwinds. The velocity curve (at P.A. = 90°) is clearly asymmetric, with the mean velocity shifted toward the obscured nuclear region.