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arXiv 2109.03142astro-ph.HE
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用POLAR测量蟹状星云脉冲星的偏振

Polarization measurements of the Crab Pulsar with POLAR

Hancheng Li, POLAR Collaboration

摘要:

POLAR是一种专用的伽马射线暴偏振仪,利用康普顿散射,从2016年9月至2017年4月从中国第二个太空实验室天宫二号获得数据。它具有宽的$\sim6$球面度视场和300 keV下的$\sim400\ cm^2$有效面积。这些特点使它成为其能量范围(15-500千电子伏)内最灵敏的仪器之一,因此能够几乎连续地监测持久性源,如射电星。PSR B 0531 +21(蟹状星云脉冲星)和PSR B1509-58都观测到了明显的折叠脉动。观测蟹状星云脉冲星与POLAR先前已被用于相位分辨光谱的蟹状星云脉冲星校准仪器响应的POLAR。在这项工作中,我们研究了一个偏振联合拟合方法的观测蟹状星云脉冲星与POLAR。与使用POLAR进行的GRB观测不同,蟹状星云脉冲星的观测因多个观测数据集而变得复杂,在此期间偏振平面也会旋转。因此,在拟合前,我们需要对不同数据集下的调制曲线进行修正,考虑到蟹状星云脉冲星在探测器局部坐标系中相对位置的旋转,以及探测器响应在不同数据集下的变化。尽管存在这些困难,而且这种源的背景信号很低,但利用POLAR数据进行偏振测量是可能的。我们将简要介绍的方法,它可以适用于任何宽视场偏振计,偏振结果的螃蟹脉冲星与POLAR。最后,还将讨论用POLAR-2(POLAR的后继者)探测脉冲星的推断能力。

英文摘要:

POLAR is a dedicated Gamma-Ray Burst polarimeter making use of Compton-scattering which took data from the second Chinese spacelab, the Tiangong-2 from September 2016 to April 2017. It has a wide Field of View of $\sim6$ steradians and an effective area of $\sim400\ cm^2$ at 300 keV. These features make it one of the most sensitive instruments in its energy range (15-500 keV), and therefore capable of almost continuously monitoring persistent sources such as pulsars. Significant folded pulsation from both PSR B0531+21 (the Crab Pulsar) and PSR B1509-58 has been observed. Observations of the Crab Pulsar with POLAR have previously been used for phase-resolved spectroscopy of the Crab Pulsar to calibrate the instrumental responses of POLAR. In this work, we investigate a polarimetric joint-fitting method for observations of the Crab Pulsar with POLAR. Unlike a GRB observation with POLAR, the observations of the Crab Pulsar are complicated by multiple observational datasets during which the polarization plane rotates as well. So before fitting, we have to correct the modulation curves under different datasets, by taking into account the rotations of the Crab Pulsar's relative position in the detctor's local coordinate, and the changes of detector response in different datasets. Despite these difficulties and the low signal to background for such sources constraining, polarization measurements were possible with the POLAR data. We will present the methodology briefly, which could be applied to any wide FoV polarimeter, and polarization results of the Crab pulsar with POLAR. Finally, the inferred ability of pulsar detection with POLAR-2 (the successor of POLAR) will also be discussed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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