A MeerKAT view of the double pulsar eclipses -- Geodetic precession of pulsar B and system geometry

Autor: Lower, M. E., Kramer, M., Shannon, R. M., Breton, R. P., Wex, N., Johnston, S., Bailes, M., Buchner, S., Hu, H., Krishnan, V. Venkatraman, Blackmon, V. A., Camilo, F., Champion, D. J., Freire, P. C. C., Geyer, M., Karastergiou, A., van Leeuwen, J., McLaughlin, M. A., Reardon, D. J., Stairs, I. H.
Rok vydání: 2023
Předmět:
Zdroj: A&A 682, A26 (2024)
Druh dokumentu: Working Paper
DOI: 10.1051/0004-6361/202347857
Popis: The double pulsar system, PSR J0737$-$3039A/B, consists of two neutron stars bound together in a highly relativistic orbit that is viewed nearly edge-on from the Earth. This alignment results in brief radio eclipses of the fast-rotating pulsar A when it passes behind the toroidal magnetosphere of the slow-rotating pulsar B. The morphology of these eclipses is strongly dependent on the geometric orientation and rotation phase of pulsar B, and their time-evolution can be used to constrain the geodetic precession rate of the pulsar. We demonstrate a Bayesian inference framework for modelling eclipse light-curves obtained with MeerKAT between 2019-2023. Using a hierarchical inference approach, we obtained a precession rate of $\Omega_{\rm SO}^{\rm B} = {5.16^{\circ}}^{+0.32^{\circ}}_{-0.34^{\circ}}$ yr$^{-1}$ for pulsar B, consistent with predictions from General Relativity to a relative uncertainty of 6.5%. This updated measurement provides a 6.1% test of relativistic spin-orbit coupling in the strong-field regime. We show that a simultaneous fit to all of our observed eclipses can in principle return a $\sim$1.5% test of spin-orbit coupling. However, systematic effects introduced by the current geometric orientation of pulsar B along with inconsistencies between the observed and predicted eclipse light curves result in difficult to quantify uncertainties. Assuming the validity of General Relativity, we definitively show that the spin-axis of pulsar B is misaligned from the total angular momentum vector by $40.6^{\circ} \pm 0.1^{\circ}$ and that the orbit of the system is inclined by approximately $90.5^{\circ}$ from the direction of our line of sight. Our measured geometry for pulsar B suggests the largely empty emission cone contains an elongated horseshoe shaped beam centered on the magnetic axis, and that it may not be re-detected as a radio pulsar until early-2035.
Comment: Abridged abstract. 13 pages, 9 figures and 2 tables
Databáze: arXiv
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