NUCLEAR AND LARGE-SCALE OUTFLOW IN NGC-1808

NGC 1808 has been studied via deep broad-band and Halpha images and longslit spectroscopy around the Na I D and Halpha lines. The suspected polar outflow is confirmed kinematically at radial velocities up to 380 km s-1 on both sides of the plane and is seen in [N II], Halpha, and Na I. In particular, Na I is seen blueshifted in absorption and redshifted in emission, providing incontrovertible proof of outflow. B-R images show that the dust plumes associated with the outflow reach approximately 3 kpc or more above the plane. The morphology of the outflow is complex. Nuclear emission and absorption line profiles show pronounced blue wings similar to those seen in far-IR luminous galaxies (FIRGs), and indicate nuclear outflow velocities up to 700 km s-1. The classification of NGC 1808 as a Seyfert 2 is reviewed and dismissed; rather, on the basis of line profiles and ratios and the presence of the ''superwind,'' NGC 1808 is probably an example of the FIRG phenomenon. Nuclear line ratios are consistent with photoionization by hot stars, but a strong N/O enhancement is indicated. Arguments are also presented that NGC 1808 is a barred galaxy and the Halpha ''jet'' consists of normal H II regions along the bar.