Instability and backreaction of massive spin-2 fields around black holes

Understand

A massive spin-2 field can grow unstably around a black hole, giving rise to a potential probe of the existence of such fields.

• In this work, we use time-domain evolutions to study such instabilities.
• Considering the linear regime by solving the equations generically governing a massive tensor field on the background of a Kerr black hole, we find that black hole spin increases the growth rate and, most significantly, the mass range of the axisymmetric (azimuthal number $m=0$) instability, which takes the form of the Gregory-Laflamme black string instability for zero spin.
• We also consider the superradiant unstable modes with $1 \leq m \leq 3$, extending previous results to higher spin-2 masses, black hole spins, and azimuthal numbers.