Improving pulsar-timing solutions through dynamic pulse fitting
Improving pulsar-timing solutions through dynamic pulse fitting
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DOI：
10.1093/mnras/stad1660
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发表时间：
2023-04
影响因子：
4.8
通讯作者：
R. Nathan;M. Miles;G. Ashton;P. Lasky;E. Thrane;D. Reardon;R. Shannon;A. Cameron
中科院分区：
文献类型：
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作者：
R. Nathan;M. Miles;G. Ashton;P. Lasky;E. Thrane;D. Reardon;R. Shannon;A. Cameron
精确的脉冲星计时对于探测纳赫兹随机引力波背景以及理解中子星的物理学是不可或缺的。传统的脉冲星计时通常使用固定的时间和频率平均模板来确定脉冲到达时间，当脉冲轮廓随时间演变时，这可能会导致精度降低。我们使用基函数说明了一种适合每个观测历元的动态计时方法。通过分别对每个历元进行拟合，我们允许脉冲形状历元的演变。我们将我们的方法应用于PSRJ1103−5403，发现有证据表明它经历了模式变化，使其成为第四颗表现出这种行为的毫秒脉冲星。我们的方法能够识别和定时单个模式，得到的定时解的均方根误差为$1.343$µS，比两种模式下的模板拟合提高了1.78%。此外，白噪声幅度降低了4.3倍，这表明拟合完整的数据集会导致模式变化被错误地归类为白噪声。白噪声的减少使这颗特定脉冲星的引力波背景信号的信噪比提高了32%。我们讨论了这种计时方法在脉冲星磁层研究中的可能应用，并进一步提高了寻找纳赫兹引力波的灵敏度。
Precision pulsar timing is integral to the detection of the nanohertz stochastic gravitational-wave background as well as understanding the physics of neutron stars. Conventional pulsar timing often uses fixed time and frequency-averaged templates to determine the pulse times of arrival, which can lead to reduced accuracy when the pulse profile evolves over time. We illustrate a dynamic timing method that fits each observing epoch using basis functions. By fitting each epoch separately, we allow for the evolution of the pulse shape epoch to epoch. We apply our method to PSR J1103−5403 and find evidence that it undergoes mode changing, making it the fourth millisecond pulsar to exhibit such behaviour. Our method, which is able to identify and time a single mode, yields a timing solution with a root-mean-square error of $1.343$ µs, a factor of 1.78 improvement over template fitting on both modes. In addition, the white-noise amplitude is reduced 4.3 times, suggesting that fitting the full data set causes the mode changing to be incorrectly classified as white noise. This reduction in white noise boosts the signal-to-noise ratio of a gravitational-wave background signal for this particular pulsar by 32 per cent. We discuss the possible applications for this method of timing to study pulsar magnetospheres and further improve the sensitivity of searches for nanohertz gravitational waves.