We present the Combined Array for Research in Millimeter Astronomy ( CARMA ) ATLAS ^ { 3 D } Â molecular gas imaging survey , a systematic study of the distribution and kinematics of molecular gas in CO-rich early-type galaxies .
Our full sample of 40 galaxies ( 30 newly mapped and 10 taken from the literature ) is complete to a ^ { 12 } CO ( 1–0 ) integrated flux of 18.5 Jy km s ^ { -1 } , and it represents the largest , best-studied sample of its type to date .
A comparison of the CO distribution of each galaxy to the g - r color image ( representing dust ) shows that the molecular gas and dust distributions are in good agreement and trace the same underlying interstellar medium .
The galaxies exhibit a variety of CO morphologies , including discs ( 50 % ) , rings ( 15 % ) , bars+rings ( 10 % ) , spiral arms ( 5 % ) , and mildly ( 12.5 % ) and strongly ( 7.5 % ) disrupted morphologies .
There appear to be weak trends between galaxy mass and CO morphology , whereby the most massive galaxies in the sample tend to have molecular gas in a disc morphology .
We derive a lower limit to the total accreted molecular gas mass across the sample of 2.48 \times 10 ^ { 10 } ~ { } M _ { \odot } , or approximately 8.3 \times 10 ^ { 8 } ~ { } M _ { \odot } per minor merger within the sample , consistent with minor merger stellar mass ratios .