FEEDING THE NUCLEAR STARBURST IN NGC6946

Abstract

We present the highest angular resolution (0.6 arcsec) and most sensitive CO(2-1) and (1-0) observations ever made of the nuclear region of the nearby late type (Scd) spiral galaxy NGC 6946. The data - obtained with the Plateau de Bure interferometer - resolve for the first time the gas morphology inside the central 300 pc of NGC 6946. The CO maps reveal an S-shaped spiral running through a small-scale gas disk centered on the galaxy nucleus. The disk has a radius of ͠ 20 pc and shows signs for radial streaming motion towards the nucleus. Our findings suggest that significant amounts of molecular gas are currently being funneled into the very nucleus of NGC 6946, which is undergoing a period of intense star formation. Our observations provide a detailed test for models of nuclear gas spirals inside the inner Lindblad resonance as a possible funneling mechanism towards galactic nuclei, and will be used to constrain the efficiency of nuclear star formation in NGC 6946.