Detection and Confirmation of Interstellar Acetic Acid

We have detected acetic acid (CH3COOH) in the Sgr B2 Large Molecule Heimat source using the Berkeley-Illinois-Maryland Association (BIMA) Array and the Caltech Owens Valley Radio Observatory (OVRO) Millimeter Array. With the BIMA array, we initially detected the 8*,8-7*,7 A blend near 90.2 GHz. The corresponding line from the E symmetry species was sought but may be blended with a line from another species. Interstellar CH3COOH was confirmed using the OVRO array, with which we detected the 9*,9-8*,8 E blend near 100.9 GHz. The corresponding line from the A symmetry species was sought but was found to be blended with the 71-70 E line of CH3SH. Our CH3COOH observations represent the first detection and confirmation of an interstellar molecule using interferometric arrays; all past detections and confirmations of new molecules have been made on the basis of single-element telescope observations.