We present aperture synthesis high-resolution ( \sim 7 ^ { \prime \prime } \times 3 ^ { \prime \prime } ) observations in CO ( J = 1 - 0 ) line , HCN ( J = 1 - 0 ) line , and 95 GHz continuum emission toward the central ( \sim 1.5 kpc ) region of the nearby barred spiral galaxy M 83 with the Nobeyama Millimeter Array .
Our high-resolution CO ( J = 1 - 0 ) mosaic map depicts the presence of molecular ridges along the leading sides of the stellar bar and nuclear twin peak structure .
On the other hand , we found the distribution of the HCN ( J = 1 - 0 ) line emission which traces dense molecular gas ( n _ { H _ { 2 } } > a few \times 10 ^ { 4 } { cm } ^ { -3 } ) shows nuclear single peak structure and coincides well with that of the 95 GHz continuum emission which traces massive starburst .
The peaks of the HCN ( J = 1 - 0 ) line and the 95 GHz continuum emission are not spatially coincident with the optical starburst regions traced by the HST V-band image .
This suggests the existence of deeply buried ongoing starburst due to strong extinction ( A _ { V } \sim 5 mag ) near the peaks of the HCN ( J = 1 - 0 ) line and the 95 GHz continuum emission .
We found that the HCN ( J = 1 - 0 ) /CO ( J = 1 - 0 ) intensity ratio R _ { HCN / CO } correlates well with extinction-corrected SFE in the central region of M 83 at a resolution of 7 ^ { \prime \prime } .5 ( \sim 160 pc ) .
This suggests that SFE is controlled by dense gas fraction traced by R _ { HCN / CO } even on a Giant Molecular cloud Association ( GMA ) scale .
Moreover , the correlation between R _ { HCN / CO } and the SFE in the central region of M 83 seems to be almost coincident with that of the \citet gao2004a sample .
This suggests that the correlation between R _ { HCN / CO } and the SFE on a GMA ( \sim 160 pc ) scale found in M 83 is the origin of the global correlation on a few kpc scale shown by \citet gao2004a .