ALMA Observations of Warm Dense Gas in NGC 1614 - Breaking of the Star Formation Law in the Central Kiloparsec

We present ALMA Cycle-0 observations of the CO (6-5) line emission and of the 435 {$μ$}m dust continuum emission in the central kiloparsec of NGC 1614, a local luminous infrared galaxy at a distance of 67.8 Mpc (1$\{$$^{\prime \prime }$$\}$= 329 pc). The CO emission is well resolved by the ALMA beam (0.''26 {\times} 0.''20) into a circumnuclear ring, with an integrated flux of f $_{ CO(6-5)}$ = 898 ({\plusmn} 153) Jy km s$^{-1}$, which is 63({\plusmn} 12)% of the total CO (6-5) flux measured by Herschel. The molecular ring, located between 100 pc łt} r łt} 350 pc from the nucleus, looks clumpy and includes seven unresolved (or marginally resolved) knots with median velocity dispersion of \~{}40 km s$^{-1}$. These knots are associated with strong star formation regions with {$Σ$}$_{SFR}$ \~{} 100 M $_{&sun;}$ yr$^{-1}$ kpc$^{-2}$ and {$Σ$} $_{Gas}${\tilde} 10⁴ $\{$M$\}$\_{\sun} pc$^{-2}$. The non-detections of the nucleus in both the CO (6-5) line emission and the 435 {$μ$}m continuum rule out, with relatively high confidence, a Compton-thick active galactic nucleus in NGC 1614. Comparisons with radio continuum emission show a strong deviation from an expected local correlation between {$Σ$}$_{Gas}$ and {$Σ$}$_{SFR}$, indicating a breakdown of the Kennicutt-Schmidt law on the linear scale of \~{}100 pc. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.