NR Simulations of PPI-Unstable BH-Disk Systems: BH Spin, Magnetic Fields, and Gravitational Wave Detectability

Accretion disks around BHs are an under-studied potential GW source. The hydrodynamic Papaloizou-Pringle Instability (PPI) can cause persistent orbiting matter clumps to grow and produce copious GWs. Via full numerical relativity simulations of self-gravitating disks, we have extended the understanding of these BH-disk systems in two new ways. First, we conducted the first-ever study of the PPI around spinning BHs ($a/M = 0.7$). We found that, in addition to slightly shifting orbital frequencies, prograde spin can reduce the accretion rate and extend GW signal lifetimes. Systems of $10 M_\odot$ - relevant for BHNS mergers - could be detectable by Cosmic Explorer out to $\sim300$ Mpc, while DECIGO (LISA) could detect systems of $1000 M_\odot$ ($10^5M_\odot$) - relevant for disks forming in collapsing supermassive stars - out to cosmological redshift of $z\sim5$ ($z\sim 1$). Second, we investigated the impact of magnetic fields on the PPI.