Extreme Variation in Star Formation Efficiency across a Compact, Starburst Disk Galaxy

We report on the internal distribution of star formation efficiency in IRAS 08339+6517 (hereafter IRAS08), using $\sim$200~pc resolution CO(2-1) observations from NOEMA. The molecular gas depletion time changes by 2 orders-of-magnitude disk-like values outer parts to less than 10$^8$~yr inside half-light radius. This translates a per free-fall that also orders-of-magnitude, reaching 50-100\%, different local spiral galaxies and typical assumption constant, low efficiencies. Our target is compact, massive disk galaxy has SFR 10$\times$ above $z=0$ main-sequence; Toomre $Q\approx0.5-0.7$ high velocity dispersion ($\sigma_{mol}\approx 25$~km~s$^{-1}$). find IRAS08 similar other rotating, starburst literature resolved $\Sigma_{SFR}\propto\Sigma_{mol}^N$ relation. By combining studies we distance main-sequence strong indicator Kennicutt-Schmidt powerlaw slope, with slopes $N\approx1.6$ for starbursts 100-10$^4$~M$_{\odot}$~pc$^{-2}$. consistent scenario which violent instabilities drive rapid inflows gas. It Toomre-$Q$, at all radii inflow timescale time, flat metallicity gradients IRAS08. consider these results light popular theories, general most tension theories constant. argue need spatial CO are larger number targets.