Probing Relativistic Winds : The Case of PSR J 0737 − 3039 A and
Probing Relativistic Winds : The Case of PSR J 0737 − 3039 A and
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探测相对论风：PSR J 0737 – 3039 A 和
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
V. Kaspi
中科院分区：
文献类型：
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作者：
J. Arons;D. Backer;A. Spitkovsky;V. Kaspi
我们认为，在最近发现的双脉冲星系统PSRJ0737−3039A&B中，磁鞘中的同步加速器吸收是脉冲星B磁层周围形成蚕茧的现象的根源。磁鞘包裹着脉冲星B的磁层，来自A的相对论风与B的磁场相撞。如果这个模型是正确的，它预测日食的清除频率将高于迄今报告的观测频率(名义上，高于ν∼5 GHz)。该模型还预测同步辐射在几到10μJy的水平上，在可能存在轨道调制的情况下在ν∼2−5 GHz达到峰值。我们使用简化的半解析模型来解释B磁层的结构，结果表明，A风的动压将B的磁场限制在离B半径小于50,000公里的范围内，小于B的光柱半径，在“白天”一侧(面向A的一侧)。在B的下游(“夜间”)，B形成一个磁尾。我们使用粒子模拟来包括磁层旋转的影响，表明磁鞘具有不对称的密度分布，这可能是观测到的日食不对称的原因。我们基于模拟中观察到的磁场重联，使用简单的估计来推导出B上的“螺旋桨”自转扭矩，这是从这颗恒星提取角动量的主要模式。将这个力矩应用于B的观测到的自旋，得到一个极偶极磁场∼7×10Gauss(磁矩μB∼3.5×10cgs)。这个扭矩有一个单位的制动指数。我们表明，只有当A风的密度比现有流行的脉冲星成对模型的预期大4个数量级时，该模型才能解释已知的日食。我们讨论了这一结果对我们对脉冲星物理的一般理解的影响。我们的提案在Kaspi等人的文章中作了定性的概述。(2004)和Demorest等人。(2004)。自这些论文发表以来，Lyutikov(2004)也提出了类似的建议。
We propose synchrotron absorption in a magnetosheath forming a cocoon around the magnetosphere of pulsar B to be the origin of the eclipse phenomena seen in the recently discovered double pulsar system PSR J0737−3039 A & B. The magnetosheath enfolds the magnetosphere of pulsar B, where the relativistic wind from A collides with B’s magnetic field. If this model is correct, it predicts the eclipses will clear at frequencies higher than those of the observations reported to date (nominally, above ν ∼ 5GHz). The model also predicts synchrotron emission at the level of a few to 10μJy, peaking at ν ∼ 2 − 5GHz with possible orbital modulation. We use simplified semi-analytic models to elucidate the structure of the B magnetosphere, showing that the A wind’s dynamic pressure confines B’s magnetic field to within a radius less than 50,000 km from B, smaller than B’s light cylinder radius, on the “daytime” side (the side facing A). Downstream of B (“nighttime”), B forms a magnetotail. We use particle-in-cell simulations to include the effects of magnetospheric rotation, showing that the magnetosheath has an asymmetric density distribution which may be responsible for the observed eclipse asymmetries. We use simple estimates based upon the magnetic reconnection observed in the simulations to derive a “propellor” spindown torque on B, which is the dominant mode of angular momentum extraction from this star. Application of this torque to B’s observed spindown yields a polar dipole field ∼ 7 × 10Gauss (magnetic moment μB ∼ 3.5× 10 cgs). This torque has a braking index of unity. We show that the model can explain the known eclipses only if the A wind’s density is at least 4 orders of magnitude greater than is expected from existing popular models of pair creation in pulsars. We discuss the implications of this result for our general understanding of pulsar physics. Our proposal was qualitatively outlined in Kaspi et al. (2004) and Demorest et al. (2004). Since those papers’ appearance, a similar proposal has been made by Lyutikov (2004).