A new technique for timing the double pulsar system

TL;DR

This paper introduces a geometrical model to analyze the timing of sub-pulses in the double pulsar system PSR J0737-3039, enabling insights into pulsar rotation, magnetospheric processes, and mass ratio estimation.

Contribution

The paper presents a novel geometrical approach to measure sub-pulse delays, linking them to pulsar rotation and system parameters, which was not previously available.

Findings

Model predicts sub-pulse delays based on pulsar geometry.

Allows determination of A's rotation sense relative to orbit.

Provides independent mass ratio estimates for the pulsars.

Abstract

In 2004, McLaughlin et al. discovered a phenomenon in the radio emission of PSR J0737-3039B (B) that resembles drifting sub-pulses. The repeat rate of the sub-pulses is equal to the spin frequency of PSR J0737-3039A (A); this led to the suggestion that they are caused by incidence upon B's magnetosphere of electromagnetic radiation from A. Here we describe a geometrical model which predicts the delay of B's sub-pulses relative to A's radio pulses. We show that measuring these delays is equivalent to tracking A's rotation from the point of view of an hypothetical observer located near B. This has three main astrophysical applications: (a) to determine the sense of rotation of A relative to its orbital plane; (b) to estimate where in B's magnetosphere the radio sub-pulses are modulated and (c) to provide an independent estimate of the mass ratio of A and B. The latter might improve existing tests of gravitational theories using this system.