Long Term Study of the Double Pulsar J0737-3039 with XMM-Newton: pulsar timing

TL;DR

This study presents precise X-ray timing of the double pulsar system PSR J0737-3039, revealing stable pulsations, wind-companion interactions, and orbital flux variability, enhancing understanding of pulsar magnetospheres and wind interactions.

Contribution

First accurate X-ray timing of PSR J0737-3039A and B, showing stable pulsations, wind interaction effects, and orbital flux variability, advancing knowledge of pulsar wind-magnetosphere dynamics.

Findings

Detected PSR A pulsations with unprecedented timing accuracy.

Confirmed X-ray emission from PSR B after radio disappearance.

Identified orbital flux variability (~7%) suggesting bow-shock interactions.

Abstract

The relativistic double neutron star binary PSR J0737-3039 shows clear evidence of orbital phase-dependent wind-companion interaction, both in radio and X-rays. In this paper we present the results of timing analysis of PSR J0737-3039 performed during 2006 and 2011 XMM-Newton Large Programs that collected ~20,000 X-ray counts from the system. We detected pulsations from PSR J0737-3039A (PSR A) through the most accurate timing measurement obtained by XMM-Newton so far, the spin period error being of 2x10^-13 s. PSR A's pulse profile in X-rays is very stable despite significant relativistic spin precession that occurred within the time span of observations. This yields a constraint on the misalignment between the spin axis and the orbital momentum axis Delta_A ~6.6^{+1.3}_{-5.4} deg, consistent with estimates based on radio data. We confirmed pulsed emission from PSR J0737-3039B (PSR B) in X-rays even after its disappearance in radio. The unusual phenomenology of PSR B's X-ray emission includes orbital pulsed flux and profile variations as well as a loss of pulsar phase coherence on time scales of years. We hypothesize that this is due to the interaction of PSR A's wind with PSR B's magnetosphere and orbital-dependent penetration of the wind plasma onto PSR B closed field lines. Finally, the analysis of the full XMM-Newton dataset provided evidences of orbital flux variability (~7%) for the first time, involving a bow-shock scenario between PSR A's wind and PSR B's magnetosphere.