Near- and Mid-IR Imaging of the Nuclear Starburst in NGC 3079

Abstract

The nearly edge-on Sc galaxy NGC 3079 displays strong nuclear optical emission lines of Ha, Hβ, [NII], [SII], [OI] and [OIII], and has been classified as a LINER based on the widths and relative fluxes of these lines. Observations at a variety of wavelengths have provided evidence for both a weak AGN and a starburst in and around the nucleus. Strong far-infrared emission (Soifer et al. 1987), extended mid-infrared emission (Lawrence et al. 1985), and the presence of a very large mass of molecular gas, nearly 10¹⁰ M_⊙ (Irwin and Sofue 1992), lying within the central kpc, all argue for a central starburst. The high luminosity and small physical size of the nuclear H₂O megamaser (Henkel et al. 1984, Haschick et al. 1990), together with the multi-component 6 cm source within the central 1 pc (Irwin and Seaquist 1988) may imply the presence of an active nucleus.