A wide latitude CO survey of the third galactic quadrant.

The results of an extensive survey toward the third quadrant in the J = 1-0 transition of CO are presented. The survey resolution is 0.5 deg and it is fully sampled from l = 210-279 deg, b = + or - 5 deg with a few extensions. The survey results are presented in the form of l, b and l, v contour maps which form a useful data base for statistical studies of star formation and galactic structure in the third quadrant. The survey has revealed the presence of intense and widespread CO emission between l approximately 255 and 279 deg, the properties of which are consistent with previous suggestions that a spiral arm is viewed end-on toward Vela. Numerous correlations between CO and HI emission in the third quadrant are discussed. Molecular counterparts to Lindblad's (1967) H, I arm, and possibly the L arm are identified, although no evidence for an 'expanding ring' molecular A feature is found. A tendency for third quadrant clouds to fall below the IAU plane is noted and is interpreted as evidence for a warp in the molecular disk. Molecular clouds associated with the OB associations Canis Major OB2, Puppis OB2, and Puppis OB3 are identified.