arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.01594astro-ph.HE
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来自Vela脉冲星2016年故障的超流惯性矩的贝叶斯估计

Bayesian estimate of the superfluid moments of inertia from the 2016 glitch in the Vela pulsar

Alessandro Montoli, Marco Antonelli, Fabio Magistrelli, Pierre Pizzochero

摘要:

在船帆座脉冲星上观测到的第一个脉冲间毛刺为研究中子星的内部动力学打开了一扇新的窗口。我们研究了脉冲星毛刺的最小三分量模型,通过求解它与一般的初始条件。目的是使用该解决方案通过采用贝叶斯方法拟合2016年船帆座故障的数据,并获得模型物理参数和观测参数(如故障上升时间和弛豫时间尺度)的概率分布。通过贝叶斯推断实现拟合。由于假信号时间附近的定时残差的增加,一个额外的磁层分量被添加到三分量模型来处理这一现象。一个物理上合理的,无信息的先验模型的参数设置,使后验分布可以与微物理计算获得的信息进行比较。通过考虑一个模型与收紧先验的转动惯量分数,并通过比较它与原始模型的贝叶斯模型选择,我们研究了一个壳限超流体油藏的可能性。我们得到了超流组分的转动惯量分数的后验分布、耦合参数和组分之间的初速度滞后。对推断后验的分析也证实了该毛刺中存在过冲,并在毛刺上升时间尺度上设置了$\sim 6\,$ s的上限。两个模型之间的比较与不同的先验的转动惯量分数似乎表明,需要一个核心参与的毛刺现象,无论不确定的夹带耦合强度。

英文摘要:

The observation of the first pulse-to-pulse glitch in the Vela pulsar opens a new window on the internal dynamics of neutron stars. We study the minimal three-component model for pulsar glitches by solving it with generic initial conditions. The purpose is to use this solution to fit the data of the 2016 Vela glitch by employing a Bayesian approach and to obtain a probability distribution for the physical parameters of the model and for observational parameters, such as the glitch rise time and the relaxation timescale. The fit is achieved through Bayesian inference. Due to the presence of an increase in the timing residuals near the glitch time, an extra magnetospheric component was added to the three-component model to deal with this phenomenon. A physically reasonable, non-informative prior was set on the parameters of the model, so that the posterior distribution could be compared with information obtained from microphysical calculations. By considering a model with a tightened prior on the moment of inertia fractions and by comparing it with the original model by means of Bayesian model selection, we studied the possibility of a crust-limited superfluid reservoir. We obtained the posterior distribution for the moment of inertia fractions of the superfluid components, the coupling parameters, and the initial velocity lags between the components. An analysis of the inferred posterior also confirmed the presence of an overshoot in that glitch and set an upper limit of $\sim 6\,$s on the glitch rise timescale. The comparison between the two models with different priors on the moment of inertia fractions appears to indicate a need for a core participation in the glitch phenomenon, regardless of the uncertain strength of the entrainment coupling.

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