  We report the production of ultracold RbCs molecules in the rovibronic ground
state, i.e., $X^1\Sigma^+ (v=0, J=0)$, by short-range photoassociation to the
$2^3\Pi_{0}$ state followed by spontaneous emission. We use narrowband
depletion spectroscopy to probe the distribution of rotational levels formed in
the $X ^1\Sigma^+(v=0)$ state. We conclude, based on selection rules, that the
primary decay route to $X ^1\Sigma^+(v=0)$ is a two-step cascade decay that
leads to as much as $33\%$ branching into the $J=0$ rotational level. The
experimental simplicity of our scheme opens up the possibility of easier access
to the study and manipulation of ultracold heteronuclear molecules in the
rovibronic ground state.
