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arXiv 0911.3798astro-ph.HEastro-ph.SR
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脉冲星剖面的旋转不对称性

Rotational asymmetry of pulsar profiles

J. Dyks, G. A. E. Wright, P. Demorest

摘要:

本文分析了旋转对快速旋转(毫秒)双星脉冲轮廓形状的影响。共转有两个相反的效应:1)通过像差和延迟(AR)使尾侧(TS)的焦散增强,其将发射挤压到更窄的相位间隔中; 2)由关于偶极轴的曲率辐射的不对称性引起的TS的减弱。在惯性观测器的框架(IOF)中的电子轨迹的曲率半径的分析,使这两种效果被认为是在一起。我们证明,对于偶极磁场线TS存在一个“焦散相”,超过该相就不能观察到发射。该阶段对应于IOF轨迹的零(或最小)曲率和发射的最大聚束。S形PA曲线中的偏振角(PA)的最大梯度也与曲率最小值相关联,并且发生在完全相同的相位处。轨道曲率相对于偶极轴的不对称性影响曲率发射率和对产生的效率,这表明在焦散相的最小值。在固定的高度范围内的发射,如预期的毫秒双星,导致广泛的领先配置文件和尖锐的峰值与TS上的截止相位。我们将我们的结果应用于5 ms脉冲星J1012+5307的主脉冲。

英文摘要:

We analyse the influence of rotation on shapes of pulse profiles of fast-rotating (millisecond) pulsars. Corotation has two opposing effects: 1) the caustic enhancement of the trailing side (TS) by aberration and retardation (AR), which squeezes the emission into a narrower phase interval; 2) the weakening of the TS caused by the asymmetry of curvature radiation about the dipole axis. Analysis of the radii of curvature of electron trajectories in the inertial observer's frame (IOF) enables these two effects to be considered together. We demonstrate that for dipolar magnetic field lines on the TS there exists a `caustic phase' beyond which no emission can be observed. This phase corresponds to the zero (or minimum) curvature of the IOF trajectories and maximum bunching of the emission. The maximum gradient of polarisation angle (PA) in the S-shaped PA curve is also associated with the curvature minimum and occurs at exactly the same phase. The asymmetry of trajectory curvature with respect to the dipole axis affects the curvature emissivity and the efficiency of pair production, suggesting a minimum at the caustic phase. Emission over a fixed range of altitudes, as expected in millisecond pulsars, leads to broad leading profiles and sharp peaks with a cutoff phase on the TS. We apply our results to the main pulse of the 5 ms pulsar J1012+5307.

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