We present our high-resolution ( 0 ^ { \prime \prime } .15 \times 0 ^ { \prime \prime } .13 , \sim 34 pc ) observations of the CO ( 6 - 5 ) line emission , which probes the warm and dense molecular gas , and the 434 \mu m dust continuum emission in the nuclear region of the starburst galaxy IC 5179 , conducted with the Atacama Large Millimeter Array ( ALMA ) .
The CO ( 6 - 5 ) emission is spatially distributed in filamentary structures with many dense cores and shows a velocity field that is characteristic of a circum-nuclear rotating gas disk , with 90 % of the rotation speed arising within a radius of \lesssim 150 pc .
At the scale of our spatial resolution , the CO ( 6 - 5 ) and dust emission peaks do not always coincide , with their surface brightness ratio varying by a factor of \sim 10 .
This result suggests that their excitation mechanisms are likely different , as further evidenced by the Southwest to Northeast spatial gradient of both CO-to-dust continuum ratio and Pa- \alpha equivalent width .
Within the nuclear region ( radius \sim 300 pc ) and with a resolution of \sim 34 pc , the CO line flux ( dust flux density ) detected in our ALMA observations is 180 \pm 18 Jy km s ^ { -1 } ( 71 \pm 7 mJy ) , which account for 22 % ( 2.4 % ) of the total value measured by Herschel .