We present \lesssim 1 kpc resolution ^ { 12 } CO imaging study of 37 optically-selected local merger remnants using new and archival interferometric maps obtained with ALMA , CARMA , SMA and PdBI .
We supplement a sub-sample with single-dish measurements obtained at the NRO 45 m telescope for estimating the molecular gas mass ( 10 ^ { 7 - 11 } M _ { \sun } ) , and evaluating the missing flux of the interferometric measurements .
Among the sources with robust CO detections , we find that 80 % ( 24/30 ) of the sample show kinematical signatures of rotating molecular gas disks ( including nuclear rings ) in their velocity fields , and the sizes of these disks vary significantly from 1.1 kpc to 9.3 kpc .
The size of the molecular gas disks in 54 % of the sources is more compact than the K -band effective radius .
These small gas disks may have formed from a past gas inflow that was triggered by a dynamical instability during a potential merging event .
On the other hand , the rest ( 46 % ) of the sources have gas disks which are extended relative to the stellar component , possibly forming a late-type galaxy with a central stellar bulge .
Our new compilation of observational data suggests that nuclear and extended molecular gas disks are common in the final stages of mergers .
This finding is consistent with recent major-merger simulations of gas rich progenitor disks .
Finally , we suggest that some of the rotation-supported turbulent disks observed at high redshifts may result from galaxies that have experienced a recent major merger .