Extending the Observational Frequency Range for Gravitational Waves in a Pulsar Timing Array

Abstract

We provide an observation method for gravitational waves using a pulsar timing array to extend the observational frequency range up to the rotational frequency of pulsars. For this purpose, we perform an analysis of a perturbed electromagnetic wave in perturbed spacetime from the field perspective. We apply the analysis to the received electromagnetic waves in a radio telescope, which partially composes the periodic electromagnetic pulse emitted by a pulsar. For simple observation, two frequency windows are considered. For each window, we propose gauge-invariant quantities and discuss their observations.

Observation of Gravitational Waves by Invariants for Electromagnetic Waves

“…To consider the perturbed EMWs in general, a full electromagnetic analysis is required. There have been approaches to directly solving the Maxwell equation for the perturbed EMWs (Calura & Montanari 1999;Mieling et al 2021;Park & Kim 2021;Park 2022). However, because their applications were limited to the domain of geometrical optics, they were only to verify the results already derived from geometrical optics or to re-derive in other ways.…”