A CO survey of the entire northern sky

The extension was carried out with the same telescope as was used for the plane survey, the CfA 1.2m, and perfectly meshes with its irregular boundaries in latitude. A total of 382,202 CO(1-0) spectra uniformly sample the high-latitude sky with a true-angle spacing of 0.25{deg} or better.

The final reduced and folded spectra have a uniform sensitivity of 0.18K in 0.65km/s channels and provide a velocity coverage of +/-47.1km/s. We describe the observational techniques and the data reduction and provide various summary maps of the spatial and velocity distributions of CO emission over the northern sky, and a catalog of the molecular clouds we found there. We also describe the CO spectral line data cubes that we have made available online.