Gueroult Renaud, Shi Yuan, Rax Jean-Marcel, Fisch Nathaniel J
LAPLACE, Université de Toulouse, CNRS, INPT, UPS, 31062, Toulouse, France.
Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA.
Nat Commun. 2019 Jul 19;10(1):3232. doi: 10.1038/s41467-019-11243-4.
Pulsars are rotating neutron stars emitting lighthouse-like beams. Owing to their unique properties, pulsars are a unique astrophysical tool to test general relativity, inform on matter in extreme conditions, and probe galactic magnetic fields. Understanding pulsar physics and emission mechanisms is critical to these applications. Here we show that mechanical-optical rotation in the pulsar magnetosphere affects polarisation in a way which is indiscernible from Faraday rotation in the interstellar medium for typical GHz observations frequency, but which can be distinguished in the sub-GHz band. Besides being essential to correct for possible systematic errors in interstellar magnetic field estimates, this result offers a unique means to determine the rotation direction of pulsars, providing additional constraints on magnetospheric physics. With the ongoing development of sub-GHz observation capabilities, our finding promises discoveries, such as the spatial distribution of pulsars rotation directions, which could exhibit potentially interesting, but presently invisible, correlations or features.
脉冲星是旋转的中子星，会发射类似灯塔的光束。由于其独特的性质，脉冲星是一种独特的天体物理工具，可用于检验广义相对论、了解极端条件下的物质情况以及探测星系磁场。理解脉冲星物理和发射机制对于这些应用至关重要。我们在此表明，脉冲星磁层中的机械-光学旋转对极化的影响，在典型的GHz观测频率下，与星际介质中的法拉第旋转难以区分，但在亚GHz频段可以区分。除了对于校正星际磁场估计中可能存在的系统误差至关重要外，这一结果还提供了一种确定脉冲星旋转方向的独特方法，为磁层物理提供了额外的限制。随着亚GHz观测能力的不断发展，我们的发现有望带来新的发现，例如脉冲星旋转方向的空间分布，这可能展现出潜在有趣但目前不可见的相关性或特征。
