  We present a method for solving the constraint equations in the Hassan-Rosen
bimetric theory to determine the initial data for the gravitational collapse of
spherically symmetric dust. The setup leads to equations similar to those for a
polytropic fluid in general relativity, here called a generalized Lane-Emden
equation. Using a numerical code which solves the evolution equations in the
standard 3+1 form, we also obtain a short term development of the initial data
for these bimetric polytropes. The evolution highlights some important features
of the bimetric theory such as the interwoven and oscillating null cones
representing the essential nonbidiagonality in the dynamics of the two metrics.
The simulations are in the strong-field regime and show that, at least at an
early stage, the collapse of a dust cloud is similar to that in general
relativity, and with no instabilities, albeit with small oscillations in the
metric fields.
