ALMA Observations of Giant Molecular Clouds in the Starburst Dwarf
  Galaxy Henize 2-10
  We present new ${ }^{12}$CO(J=1-0) observations of Henize 2-10, a blue
compact dwarf galaxy about 8.7 Mpc away, taken with the Atacama Large
Millimeter Array. These are the highest spatial and spectral resolution
observations, to date, of the molecular gas in this starburst galaxy. We
measure a molecular mass of $1.2\times10^8 M_\odot$ in Henize 2-10, and most of
the molecular gas is contained within a region having a size of about 310 pc.
We use the CPROPS algorithm to identify 119 resolved giant molecular clouds
distributed throughout the galaxy, and the molecular gas contained within these
clouds make up between 45 to 70% of the total molecular mass. The molecular
clouds in Henize 2-10 have similar median sizes (~26 pc), luminous masses (~$
4\times 10^5$ $M_\odot$), and surface densities (~$180$ $M_\odot$ pc$^{-2}$) to
Milky Way clouds. We provide evidence that Henize 2-10 clouds tend to be in
virial equilibrium, with the virial and luminous masses scaling according to
$M_{vir}\propto M_{lum}^{1.2\pm0.1}$, similar to clouds in the Milky Way.
However, we measure a scaling relationship between luminous mass and size,
$M_{vir}\propto R^{3.0\pm0.3}$, that is steeper than what is observed in Milky
Way clouds. Assuming Henize 2-10 molecular clouds are virialized, we infer
values of the CO-to-H$_2$ conversion factor ranging from 0.5 to 13 times the
standard value in the Solar Neighborhood. Given star formation efficiencies as
low as 5%, the most massive molecular clouds in Henize 2-10 currently have
enough mass to form the next generation of super-star clusters in the galaxy.
