Program: GS-2013B-SV-999

We propose to observe a small sample of weak-continuum, dwarf galaxies to investigate the excitation of molecular hydrogen in massive star-forming complexes. In the usable fraction of our previous allocation we were able to observe one of our targets, NGC5461. This dataset unambiguously shows that the gas is excited in low density photo-dissociation regions, contrary to the widespread assumption in the literature that the H2 in galaxies is predominantly shock excited. The weakness of the dwarf galaxy continua permits detection of the higher level H2 transitions which are essential to determine the gas excitation and relative contributions of thermal and UV-excited gas.