论文标题

部分可观测时空混沌系统的无模型预测

An unusual pulse shape change event in PSR J1713+0747 observed with the Green Bank Telescope and CHIME

论文作者

Jennings, Ross J., Cordes, James M., Chatterjee, Shami, McLaughlin, Maura A., Demorest, Paul B., Arzoumanian, Zaven, Baker, Paul T., Blumer, Harsha, Brook, Paul R., Cohen, Tyler, Crawford, Fronefield, Cromartie, H. Thankful, DeCesar, Megan E., Dolch, Timothy, Ferrara, Elizabeth C., Fonseca, Emmanuel, Good, Deborah C., Hazboun, Jeffrey S., Jones, Megan L., Kaplan, David L., Lam, Michael T., Lazio, T. Joseph W., Lorimer, Duncan R., Luo, Jing, Lynch, Ryan S., McKee, James W., Madison, Dustin R., Meyers, Bradley W., Mingarelli, Chiara M. F., Nice, David J., Pennucci, Timothy T., Perera, Benetge B. P., Pol, Nihan S., Ransom, Scott M., Ray, Paul S., Shapiro-Albert, Brent J., Siemens, Xavier, Stairs, Ingrid H., Stinebring, Daniel R., Swiggum, Joseph K., Tan, Chia Min, Taylor, Stephen R., Vigeland, Sarah J., Witt, Caitlin A.

论文摘要

储层计算是预测湍流的有力工具,其简单的架构具有处理大型系统的计算效率。然而,其实现通常需要完整的状态向量测量和系统非线性知识。我们使用非线性投影函数将系统测量扩展到高维空间,然后将其输入到储层中以获得预测。我们展示了这种储层计算网络在时空混沌系统上的应用,该系统模拟了湍流的若干特征。我们表明,使用径向基函数作为非线性投影器,即使只有部分观测并且不知道控制方程,也能稳健地捕捉复杂的系统非线性。最后,我们表明,当测量稀疏、不完整且带有噪声,甚至控制方程变得不准确时,我们的网络仍然可以产生相当准确的预测,从而为实际湍流系统的无模型预测铺平了道路。

The millisecond pulsar J1713+0747 underwent a sudden and significant pulse shape change between April 16 and 17, 2021 (MJDs 59320 and 59321). Subsequently, the pulse shape gradually recovered over the course of several months. We report the results of continued multi-frequency radio observations of the pulsar made using the Canadian Hydrogen Intensity Mapping Experiment (CHIME) and the 100-meter Green Bank Telescope (GBT) in a three-year period encompassing the shape change event, between February 2020 and February 2023. As of February 2023, the pulse shape had returned to a state similar to that seen before the event, but with measurable changes remaining. The amplitude of the shape change and the accompanying TOA residuals display a strong non-monotonic dependence on radio frequency, demonstrating that the event is neither a glitch (the effects of which should be independent of radio frequency, $ν$) nor a change in dispersion measure (DM) alone (which would produce a delay proportional to $ν^{-2}$). However, it does bear some resemblance to the two previous "chromatic timing events" observed in J1713+0747 (Demorest et al. 2013; Lam et al. 2016), as well as to a similar event observed in PSR J1643-1224 in 2015 (Shannon et al. 2016).

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