Time domain calculations of scalar self-force and radiation from an orbiting point charge in Schwarzschild spacetime

Gravitational wave astronomy is a new window on violent mergers of black holes and neutron~ stars, and promises to eventually provide observations of supernovae, extreme-mass-ratio inspirals~(EMRIs) into supermassive black holes, and fluctuations in the Big Bang.~ We focus on time domain~calculations eventually relevant to understanding EMRIs but studying the scalar self-force model~problem.~ In these calculations, scalar radiation is emitted by a point scalar-charged particle in orbit about a more massive Schwarzschild black hole.~ The time domain calculations use a discontinuous~internal boundary condition representation for the point charge.~ We are implementing hyperboloidal~slicing and compactification to improve the treatment of distant and horizon boundaries.~ Results are~compared to earlier frequency domain calculations of Warburton and Barack, and to another more recently developed frequency domain code.~~