The Mopra Southern Galactic Plane CO Survey—Data Release 3

We present observations of 50 deg2of the Mopra carbon monoxide (CO) survey of the Southern Galactic Plane, covering Galactic longitudesl= 300–350° and latitudes |b| ⩽ 0.5°. These data have been taken at 0.6 arcmin spatial resolution and 0.1 km s−1spectral resolution, providing an unprecedented view of the molecular clouds and gas of the Southern Galactic Plane in the 109–115 GHzJ= 1–0 transitions of12CO,13CO, C18O, and C17O. We present a series of velocity-integrated maps, spectra, and position-velocity plots that illustrate Galactic arm structures and trace masses on the order of ~106M⊙deg−2, and include a preliminary catalogue of C18O clumps located betweenl= 330–340°. Together with the information about the noise statistics of the survey, these data can be retrieved from the Mopra CO website and the PASA data store.