Investigating molecular gas at ~500 pc scales in a star forming disk galaxy at z~2

We have resolved molecular gas in a star forming disk galaxy at z>2 down to the scale of ~500 pc. Previous observations of CO and [CI] lines on larger spatial scales have revealed bulk molecular and atomic gas properties indicating that the target is a massive disk galaxy with large gas reserves. Unlike many galaxies studied at high redshift, it lies along the upper boundary of the galaxy main sequence. Therefore this galaxy represents an under-studied, but cosmologically important population in the early universe. Our new observations of CO (4-3) highlight the clumpy molecular gas fueling star formation throughout the disk. Underlying continuum from cold dust provides a key constraint on star formation rate surface densities, allowing us to examine the star formation rate surface density scaling law in a never-before- tested regime of early universe galaxies. These observations enable an unprecedented view of the obscured star formation that is hidden to optical/UV imaging and trace molecular gas on a fine enough scale to resolve morphological traits and provide a view akin to single dish surveys in the local universe.