We use cyclic spectroscopy to perform high-frequency resolution analyses of multihour baseband Arecibo observations of the millisecond pulsar PSR B1937+21. This technique allows for the examination of scintillation features in far greater detail than is otherwise possible under most pulsar timing array observing setups. We measure scintillation bandwidths and timescales in each of eight subbands across a 200 MHz observing band in each observation. Through these measurements we obtain intra-epoch estimates of the frequency scalings for scintillation bandwidth and timescale. Thanks to our high-frequency resolution and the narrow scintles of this pulsar, we resolve scintillation arcs in the secondary spectra due to the increased Nyquist limit, which would not have been resolved at the same observing frequency with a traditional filterbank spectrum using NANOGrav’s current time and frequency resolutions, and the frequency-dependent evolution of scintillation arc features within individual observations. We observe the dimming of prominent arc features at higher frequencies, possibly due to a combination of decreasing flux density and the frequency dependence of the plasma refractive index of the interstellar medium. We also find agreement with arc curvature frequency dependence predicted by Stinebring et al. in some epochs. Thanks to the frequency-resolution improvement provided by cyclic spectroscopy, these results show strong promise for future such analyses with millisecond pulsars, particularly for pulsar timing arrays, where such techniques can allow for detailed studies of the interstellar medium in highly scattered pulsars without sacrificing the timing resolution that is crucial to their gravitational-wave detection efforts.

中文翻译：

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PSR B1937+21 的循环光谱闪烁研究。一、改进闪烁测量法的演示


我们使用循环光谱对毫秒脉冲星 PSR B1937+21 的多小时基带阿雷西博观测进行高频分辨率分析。与大多数脉冲星计时阵列观测装置相比，该技术可以更详细地检查闪烁特征。我们在每次观测中测量 200 MHz 观测频带内八个子带中每一个子带的闪烁带宽和时间尺度。通过这些测量，我们获得了闪烁带宽和时间尺度的频率缩放的历元内估计。由于我们的高频分辨率和该脉冲星的窄闪烁，我们解决了由于奈奎斯特极限增加而导致的二次光谱中的闪烁弧，而使用 NANOGrav 当前时间的传统滤波器组光谱在相同的观测频率下无法解决这一问题和频率分辨率，以及单个观测中闪烁弧特征的频率相关演化。我们观察到在较高频率下突出的电弧特征变暗，这可能是由于通量密度降低和星际介质等离子体折射率的频率依赖性的结合。我们还发现与 Stinebring 等人预测的弧曲率频率依赖性一致。在某些时代。由于循环光谱提供的频率分辨率提高，这些结果显示了未来此类毫秒脉冲星分析的巨大前景，特别是对于脉冲星计时阵列，此类技术可以在不牺牲高度散射脉冲星中的星际介质的详细研究的情况下进行。时间分辨率对于他们的引力波探测工作至关重要。