Radio pulsar beam geometry at lower frequencies: bright sources outside the Arecibo sky
Radio pulsar beam geometry at lower frequencies: bright sources outside the Arecibo sky
复制标题
低频射电脉冲星束的几何形状：阿雷西博天空外的明亮源
DOI：
10.1093/mnras/stac1302
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发表时间：
2022
影响因子：
4.8
通讯作者：
Rankin, Joanna
中科院分区：
文献类型：
--
作者：
Rankin, Joanna
我们提出脉冲星发射束分析和模型，以努力在散射允许的最低频率下检查脉冲星的几何形状和物理特性。我们考虑了位于阿雷西博天空之外的两组经过充分研究的脉冲星，第一个是根据 Jodrell Bank Gould & Lyne 勘测得出的，赤纬范围为 –35°，第二个是利用帕克斯在最南端的勘测得出的。这些脉冲星聚集了 20 世纪 90 年代末之前已知的 487 颗脉冲星，它们全部都有“B”名称。我们充分利用核心/双锥发射束模型来评估其在较低频率下的功效，并概述了不同的等离子体源对可能是其有效性的基础。分析表明，除了极少数例外，脉冲星无线电发射光束可以使用两个同心锥形光束和一个 1 GHz 的规则角度尺寸的核心光束进行定量建模。此外，较低频率下的波束形状在尺寸上逐渐变化，但在配置上没有变化。脉冲星发射束特性的差异很大程度上取决于等离子体激发是在极通量管内产生核心束还是沿着边缘产生锥形束，这似乎很大程度上取决于它们的自旋能量是否大于或小于约 1032.5ergs s−1。以核心发射为主的脉冲星倾向于沿着银河平面和银河中心方向紧密集中；而圆锥脉冲星在银河系经度和纬度上的分布更加均匀。核心主导的脉冲星也往往距离更远，尤其是在银河系内部区域。
We present pulsar emission beam analyses and models in an effort to examine pulsar geometry and physics at the lowest frequencies scattering permits. We consider two populations of well-studied pulsars that lie outside the Arecibo sky, the first drawing on the Jodrell Bank Gould & Lyne survey down to –35° declination and a second using Parkes surveys in the far south. These assemble the full sky population of 487 pulsars known before the late 1990s which conveniently all have ‘B’ names. We make full use of the core/double-cone emission beam model to assess its efficacy at lower frequencies, and we outline how different pair plasma sources probably underlie its validity. The analysis shows that with a very few exceptions pulsar radio emission beams can be modeled quantitatively with two concentric conal beams and a core beam of regular angular dimensions at 1 GHz. Further, the beamforms at lower frequencies change progressively in size but not in configuration. Pulsar emission-beam properties divide strongly depending on whether the plasma excitation is central within the polar fluxtube producing a core beam or peripheral along the edges generating conal beams, and this seems largely determined by whether their spin-down energy is greater or less than about 1032.5ergs s−1. Core emission dominated pulsars tend concentrate closely along the Galactic plane and in the direction of the Galactic center; whereas conal pulsars are somewhat more uniformly distributed both in Galactic longitude and latitude. Core dominated pulsars also tend to be more distant and particularly so in the inner Galaxy region.