The Galactic supernova remnant ( SNR ) IC 443 is one of the most studied core-collapse SNRs for its interaction with molecular clouds .
However , the ambient molecular clouds with which IC 443 is interacting have not been thoroughly studied and remain poorly understood .
Using Five College Radio Astronomy Observatory 14m telescope , we obtained fully sampled maps of \sim 1 \arcdeg \times 1 \arcdeg region toward IC 443 in the ^ { 12 } CO J = 1 - 0 and HCO ^ { + } J = 1 - 0 lines .
In addition to the previously known molecular clouds in the velocity range v _ { \mathrm { LSR } } = -6 to -1 \mathrm { km s } ^ { -1 } ( -3 \mathrm { km s } ^ { -1 } clouds ) , our observations reveal two new ambient molecular cloud components : small ( \sim 1 \arcmin ) bright clouds in v _ { \mathrm { LSR } } = -8 to -3 \mathrm { km s } ^ { -1 } ( SCs ) , and diffuse clouds in v _ { \mathrm { LSR } } = +3 to +10 \mathrm { km s } ^ { -1 } ( +5 \mathrm { km s } ^ { -1 } clouds ) .
Our data also reveal the detailed kinematics of the shocked molecular gas in IC 443 , however the focus of this paper is the physical relationship between the shocked clumps and the ambient cloud components .
We find strong evidence that the SCs are associated with the shocked clumps .
This is supported by the positional coincidence of the SCs with shocked clumps and other tracers of shocks .
Furthermore , the kinematic features of some shocked clumps suggest that these are the ablated material from the SCs upon the impact of the SNR shock .
The SCs are interpreted as dense cores of parental molecular clouds that survived the destruction by the pre-supernova evolution of the progenitor star or its nearby stars .
We propose that the expanding SNR shock is now impacting some of the remaining cores and the gas is being ablated and accelerated producing the shocked molecular gas .
The morphology of the +5 \mathrm { km s } ^ { -1 } clouds suggests an association with IC 443 .
On the other hand , the -3 \mathrm { km s } ^ { -1 } clouds show no evidence for interaction .