Ulrich Sperhake, Christopher J. Moore, Roxana Rosca, Michalis Agathos, **Davide Gerosa,** Christian D. Ott.

**Physical Review Letters **119 (2017) 201103.

arXiv:1708.03651 [gr-qc].

Supernova can be used to test gravity! …and if there’s a massive scalar field around, things get terribly interesting. Here we generalize arXiv:1602.06952 to study stellar collapse in massive scalar-tensor theories of gravity (that is, the graviton is coupled to a massive scalar field) with numerical simulations. The scalar-field mass introduces a dispersion relation, and different GW frequencies travel at different speeds. It might even make sense to target historic supernovae: maybe the tail of the signal is still coming to us!