标题： 用二维高斯过程回归测量脉冲星轮廓变化 显示英文标题

标题： Measuring pulsar profile variations with 2-D Gaussian process regression

摘要： 射电脉冲星脉冲轮廓的时间相关变化为了解其磁层的变化提供了见解。对于少数几个脉冲星（~20个），这些变化已被证明与自转减慢率相关。其中许多轮廓变化涉及不同轮廓分量相对强度的小幅（百分之几）变化，因此已采用高斯过程回归等工具来分离时间相关的轮廓变化与固有噪声。本文提出了一种计算效率更高的二维高斯过程模型近似方法，通过同时追踪时间和相位相关的信号来提高灵敏度。将此模型应用于朱德雷天文台观测的26个脉冲星，我们检测到21个脉冲星的显著轮廓形状变化。使用主成分分析，我们确认了11个脉冲星的自转减慢相关的形状变化，此前已有观察记录。此外，我们首次在7个脉冲星（PSR B0105+65、B0611+22、B0626+24、B1740-03、B1826-17、B1917+00和B2148+63）中发现自转减慢相关的形状变化。我们更详细地研究了PSR B0740-28，其轮廓形状与自转减慢之间的相关性似乎在准稳定状态下切换。值得注意的是，与更大自转减慢相关的轮廓形状有时会反转，这对我们理解正在发生的作用的物理过程提出了挑战。 显示英文摘要

摘要： Time-correlated variations in the pulse profiles of radio pulsars provide insights into changes in their magnetospheres. For a small number of pulsars (~20), these variations have been shown to correlate with spin-down rate. Many of these profile changes involve small (few percent) variations in the relative intensity of different profile components, and hence tools such as Gaussian process regression have been employed to separate the time-correlated profile variation from intrinsic noise. In this paper, we present a computationally efficient approximation of a 2-D Gaussian process model that enhances sensitivity by simultaneously tracking time- and phase-correlated signals. Applying this model to 26 pulsars observed at the Jodrell Bank Observatory, we detect significant profile shape variations in 21 pulsars. Using principal component analysis, we confirm spin-down correlated shape variations in 11 pulsars where this had been previously observed. Additionally, we find evidence of spin-down correlated shape changes in 7 pulsars for the first time (PSRs B0105+65, B0611+22, B0626+24, B1740-03, B1826-17, B1917+00, and B2148+63). We look in greater detail at PSR B0740-28, where the correlation between profile shape and spin-down itself seems to switch between quasi-stable states. Notably the profile shape associated with greater spin-down seems to invert at times, presenting a challenge to our understanding of the physical processes at work.