Gravitational radiation from magnetically funnelled supernova fallback onto a magnetar

Abstract

Protomagnetars spun up to millisecond rotation periods by supernova fallback are predicted to radiate gravitational waves via hydrodynamic instabilities for ~ 10^2 s before possibly collapsing to form a black hole. It is shown that magnetic funnelling of the accretion flow (i) creates a magnetically confined polar mountain, which boosts the gravitational wave signal, and (ii) "buries" the magnetic dipole moment, delaying the propeller phase and assisting black hole formation.

4 figures; accepted for publication in The Astrophysical Journal