使用组合望远镜的单脉冲探索科学：II. 脉冲轮廓演化与单脉冲调制

中文摘要 AI 辅助

目的。我们旨在阐明脉冲星的积分脉冲轮廓和单脉冲调制如何随射电频率演化，同时分离内在效应和传播效应。方法。我们展示了12颗射电脉冲星在多达五个频段的积分脉冲轮廓和相位分辨调制指数。我们的宽带数据集系统性地采集自南赛射电天文台望远镜和uGMRT，覆盖10 MHz至2.8 GHz的频率范围，包括NenuFAR、LOFAR FR606、uGMRT和NRT观测。我们使用多分量轮廓拟合仔细测量了脉冲宽度和散射时间。我们采用轮廓宽度缩放模型将轮廓演化分离为散射贡献和内在贡献。我们量化了脉冲星单脉冲变异性随频率的变化。结果。我们描述了脉冲轮廓演化。两颗脉冲星的散射指数与柯尔莫哥洛夫湍流相符，而大多数脉冲星具有更平坦的散射指数。这表明复杂的散射环境，由局域化湍流主导。在一些脉冲星中观察到复杂的散射行为，且大多数轮廓在200 MHz以下由散射主导。测量的内在幂律指数较小，绝对值在0到0.3之间。五颗脉冲星表现出内在宽度减小，两颗或三颗脉冲星表现出平坦行为，四颗脉冲星的轮廓宽度随频率增加。考虑到偏差，大多数脉冲星的调制参数随频率减小，而三颗脉冲星表现出平坦行为。结论。脉冲宽度演化可由内在射电波束变窄、轮廓分量的出现以及两者之间的平衡来解释。我们的调制分析表明，我们大多数脉冲星的单脉冲发射在较低射电频率下变得更加不规则，这与振幅调制增强一致。

英文摘要

Aims. We aim to illuminate how the pulsars' integrated pulse profiles and single-pulse modulation evolve with radio frequency, while separating intrinsic and propagation effects. Methods. We present integrated pulse profiles and phase-resolved modulation indices for 12 radio pulsars at up to five frequency bands. Our wideband dataset was systematically acquired with the Nancay Radio Observatory telescopes and the uGMRT, covering the frequency range 10 MHz to 2.8 GHz, including NenuFAR, LOFAR FR606, uGMRT, and NRT observations. We carefully measured the pulse widths and scattering times using multi-component profile fitting. We employed a profile width scaling model to separate the profile evolution into scattering and intrinsic contributions. We quantified the pulsars' single-pulse variability across frequency. Results. We describe the pulse profile evolution. Two pulsars have scattering indices compatible with Kolmogorov turbulence, while the majority have flatter scattering indices. This suggests complex scattering environments, dominated by localised turbulence. Complex scattering behaviour is seen in some pulsars, and most profiles are scattering-dominated below 200 MHz. The measured intrinsic power law indices are small, with absolute values between 0 and 0.3. Five pulsars exhibit decreasing intrinsic widths, two or three pulsars show flat behaviour, and four pulsars have increasing profile widths with frequency. Accounting for biases, most pulsar modulation parameters decrease with frequency, while three pulsars show flat behaviour. Conclusions. The pulse width evolution is explained by intrinsic radio beam narrowing, the emergence of profile components, and the balance between the two. Our modulation analysis indicates that the single-pulse emission from most of our pulsars becomes more erratic towards lower radio frequencies, consistent with increasing amplitude modulation.

发表机构

• LPC2E, OSUC, Univ Orleans, CNRS, CNES, Observatoire de Paris（奥尔良大学、法国国家科学研究中心、法国国家空间研究中心、巴黎天文台）
• Observatoire Radioastronomique de Nançay, Observatoire de Paris, Université PSL, Université d’Orléans, CNRS（南希射电天文观测站、巴黎天文台、巴黎文理研究大学、奥尔良大学、法国国家科学研究中心）
• Nicolaus Copernicus Astronomical Center（尼古拉·哥白尼天文中心）
• Department of Physics, IISER Bhopal（博帕尔印度科学与教育研究院物理系）
• Université de Strasbourg, CNRS, Observatoire astronomique de Strasbourg（斯特拉斯堡大学、法国国家科学研究中心、斯特拉斯堡天文观测站）

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补充信息

备注

Submitted, comments welcome. Abstract shortened slightly to fit the arXiv limits