The Characteristics of Millisecond Pulsar Emission. I. Spectra, Pulse Shapes, and the Beaming Fraction
The Characteristics of Millisecond Pulsar Emission. I. Spectra, Pulse Shapes, and the Beaming Fraction
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DOI：
10.1086/305790
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发表时间：
1998-01
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通讯作者：
M. Kramer;K. Xilouris;D. Lorimer;O. Doroshenko;A. Jessner;R. Wielebinski;A. Wolszczan;F. M. F. Radioastronomie-F.-M.-F.-Radioastronomie-103349564;Bonn;H Germany;Naic;A. Observatory;Puerto Rico.;Usa;D. Astronomy;Astrophysics;P. S. University;Nral;J. Bank;UK.
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文献类型：
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作者：
M. Kramer;K. Xilouris;D. Lorimer;O. Doroshenko;A. Jessner;R. Wielebinski;A. Wolszczan;F. M. F. Radioastronomie-F.-M.-F.-Radioastronomie-103349564;Bonn;H Germany;Naic;A. Observatory;Puerto Rico.;Usa;D. Astronomy;Astrophysics;P. S. University;Nral;J. Bank;UK.
毫秒脉冲星磁层的极端物理条件，以及与正常脉冲星不同的演化史，提出了这样一个问题：这些天体的射电发射特性是否也不同。为了比较这两类脉冲星的射电辐射特性，我们利用100米埃菲尔斯伯格射电望远镜对一大批毫秒脉冲星进行了为期3年的监测。我们的样本包含一个质量非常高的同质数据集。除了一些值得注意的例外，我们的发现表明，这两组物体有许多共同的属性。对正常脉冲星和毫秒脉冲星的光谱指数的比较表明，毫秒脉冲星的光谱与正常脉冲星的光谱没有显著差异。这与之前的想法相反。然而，有证据表明，毫秒脉冲星的亮度和射电效率略低于普通脉冲星。我们证实了最近关于毫秒脉冲星的亮度之间存在多样性的说法，孤立的毫秒脉冲星的亮度比双毫秒脉冲星的亮度要低，这意味着不同的演化历史对发射性质有影响。有迹象表明，较老的毫秒脉冲星的光谱比推测较年轻的要平坦一些。我们提出的证据表明，与通常的看法相反，毫秒脉冲星的轮廓只比在正常脉冲星群体中发现的复杂一点。此外，频率剖面的发展相当缓慢，这表明磁层非常致密。轮廓的发展似乎与伴生质量和自旋周期相反，这再次表明，双星系统中的传质数量可能直接影响发射性质。毫秒脉冲星射电波束的角半径并不遵循适用于正常脉冲星的正则脉冲星模型所预测的比例。相反，它们系统性地较小，支持关键旋转周期的概念，低于该周期，这种比例将不复存在。在未来计算银河系人口的出生率时，需要考虑较小的推断光度和较窄的发射光束。
The extreme physical conditions in millisecond pulsar magnetospheres, as well as an evolutionary history that differs from that of normal pulsars, raise the question whether these objects also differ in their radio emission properties. We have monitored a large sample of millisecond pulsars for a period of 3 yr using the 100 m Effelsberg radio telescope in order to compare the radio emission properties of these two pulsar populations. Our sample comprises a homogeneous data set of very high quality. With some notable exceptions, our findings suggest that the two groups of objects share many common properties. A comparison of the spectral indices between samples of normal and millisecond pulsars demonstrates that millisecond pulsar spectra are not significantly different from those of normal pulsars. This is contrary to what has previously been thought. There is evidence, however, that millisecond pulsars are slightly less luminous and less efficient radio emitters than normal pulsars. We confirm recent suggestions that a diversity exists among the luminosities of millisecond pulsars, with the isolated millisecond pulsars being less luminous than the binary millisecond pulsars, implying that the different evolutionary history has an influence on the emission properties. There are indications that old millisecond pulsars exhibit somewhat flatter spectra than the presumably younger ones. We present evidence that, contrary to common belief, the millisecond pulsar profiles are only marginally more complex than those found among the normal pulsar population. Moreover, the development of the profiles with frequency is rather slow, suggesting very compact magnetospheres. The profile development seems to anticorrelate with the companion mass and the spin period, again suggesting that the amount of mass transfer in a binary system might directly influence the emission properties. The angular radius of radio beams of millisecond pulsars does not follow the scaling predicted from a canonical pulsar model applicable for normal pulsars. Instead, they are systematically smaller, supporting the concept of a critical rotational period below which such a scaling ceases to exist. The smaller inferred luminosity and narrower emission beams will need to be considered in future calculations of the birthrate of the Galactic population.