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arXiv 0803.3854astro-ph
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脉冲星的亚脉冲调制特性及其频率依赖性

The Subpulse Modulation Properties of Pulsars and its Frequency Dependence

Patrick Weltevrede, Ben Stappers, R. T. Edwards

摘要:

利用韦斯特博克综合射电望远镜观测了大约200颗双星的大样本,研究了它们在21和92厘米观测波长(如果可以实现的话)下的子脉冲调制。首次发现了57颗恒星的漂移子脉冲,并证实了许多其他恒星的漂移子脉冲。这导致了这样的结论:漂移的子脉冲机制很可能是发射机制本身的固有属性,尽管对于某些辐射来说,它很难或不可能被检测到。看起来,最年轻的脉冲星具有最无序的子脉冲,并且随着脉冲星年龄的增长,子脉冲变得越来越有组织地成为漂移的子脉冲。漂移子脉冲通常在两个频率处都被发现,并且在两个频率处的P3的测量值是高度相关的,示出了这种现象的宽带性质。此外,在两个频率下测量的调制指数明显相关,尽管在92 cm处它们平均可能更高。与调制指数的相关性被认为是一致的图片,其中的无线电发射是由一个漂移的子脉冲信号加上一个准稳定的信号,平均而言,在高观测频率变得更强。与以往的报道相反,P3与脉冲星年龄(或其他脉冲星参数)之间没有明显的相关性。

英文摘要:

A large sample of about two hundred pulsars have been observed to study their subpulse modulation at an observing wavelength of (when achievable) both 21 and 92 cm using the Westerbork Synthesis Radio Telescope. For 57 pulsars drifting subpulses are discovered for the first time and are confirmed for many others. This leads to the conclusion that it could well be that the drifting subpulse mechanism is an intrinsic property of the emission mechanism itself, although for some pulsars it is difficult or impossible to detect. It appears that the youngest pulsars have the most disordered subpulses and the subpulses become more and more organized into drifting subpulses as the pulsar ages. Drifting subpulses are in general found at both frequencies and the measured values of P3 at the two frequencies are highly correlated, showing the broadband nature of this phenomenon. Also the modulation indices measured at the two frequencies are clearly correlated, although at 92 cm they are on average possibly higher. The correlations with the modulation indices are argued to be consistent with the picture in which the radio emission is composed out of a drifting subpulse signal plus a quasi-steady signal which becomes, on average, stronger at high observing frequencies. There is no obvious correlation found between P3 and the pulsar age (or any other pulsar parameter) contrary to reports in the past.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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