标题： 一个 MeerKAT 观测到的双脉冲星掩食——脉冲星 B 的大地测量进动与系统几何结构 显示英文标题

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

摘要： 双脉冲星系统 PSR J0737$-$3039A/B 由两颗中子星组成，它们在高度相对论性的轨道上相互束缚，并且从地球上看几乎是侧面的。 这种排列导致快速旋转的脉冲星 A 在经过缓慢旋转的脉冲星 B 的环状磁层后方时发生短暂的无线电掩食。 这些掩食的形态强烈依赖于脉冲星 B 的几何方向和自转相位，它们的时间演化可以用来限制脉冲星的地基进动率。 我们展示了一个贝叶斯推理框架，用于建模通过 Meerkat 在 2019-2023 年间获得的掩食光变曲线。 使用分层推理方法，我们得到了脉冲星 B 的地基进动率为 $\Omega_{\rm SO}^{\rm B} = {5.16^{\circ}}^{+0.32^{\circ}}_{-0.34^{\circ}}$ 年$^{-1}$，与广义相对论的预测一致，相对不确定性为 6.5%。 这一更新的测量提供了对强场范围内相对论自旋-轨道耦合的 6.1% 测试。 我们表明，同时拟合我们观测到的所有掩食在原则上可以返回一个$\sim$1.5% 的自旋-轨道耦合测试。 然而，由于脉冲星 B 当前的几何方向引入的系统效应以及观测和预测掩食光变曲线之间的不一致性，导致难以量化不确定性。 假设广义相对论有效，我们明确显示脉冲星 B 的自旋轴偏离总角动量矢量$40.6^{\circ} \pm 0.1^{\circ}$，并且系统的轨道相对于我们的视线方向倾斜了大约$90.5^{\circ}$。 我们对脉冲星 B 的测量几何表明，主要为空的发射锥包含一个以磁场轴为中心的弯曲马蹄形光束，它可能直到 2035 年初才可能重新被检测为射电脉冲星。 显示英文摘要

摘要： 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.