A High‐Resolution Mosaic of Molecular Gas in Stephan’s Quintet

Abstract

We present high resolution CO J=1-0 observations of the molecular gas in the Hickson Compact Group Stephan's Quintet (HCG92). Our observations consist of multiple pointing and mosaics covering all the regions where CO and star formation has been detected. Within the 100'' field of view centered on the eastern-most tidal tail, we detect three clumps of emission that may be partially resolved at our resolution of 8''; two of these are new detections not previously seen in ISM studies of this region. Two of these clumps lie in the optical tidal tail, while the third lies to the southeast and is coincident with a large HI feature, but does not correspond to any features at other wavelengths. We also tentatively detect CO emission from the star forming regions in the ``Old Tail'' corresponding to recent star formation activity detected in recent UV and H$\alpha$ observations. Observations of the rest of the compact group do not show detections even though strong emission was detected with single dish telescopes, which suggests the CO emission originates from a diffuse molecular gas cloud or from more at least three separate clumps with separations of greater than around 3 kpc.