arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2408.04431astro-ph.HEastro-ph.SR
收藏

X射线脉冲星的X射线偏振测量

X-ray Polarimetry of X-ray Pulsars

Juri Poutanen, Sergey S. Tsygankov, Sofia V. Forsblom

AI总结:

利用IXPE对十几颗X射线脉冲星的观测,发现偏振角随脉冲相位的变化符合旋转矢量模型,据此确定了脉冲星几何结构并证实Her X-1中子星自由进动,还发现吸积盘风散射产生的非脉冲偏振辐射。

摘要:

由于寻常模与非常模不透明度存在巨大差异,X射线脉冲星(XRPs)的辐射曾被认为应呈强线偏振。IXPE的发射使我们得以检验这一预言。IXPE观测了十几颗X射线脉冲星,发现了随脉冲相位变化的偏振度(PD)和偏振角(PA)的变化。尽管PD呈现出与流量脉冲依赖关系相似的相当不规则的轮廓,但在大多数情况下,PA显示出与旋转矢量模型(RVM)一致的平滑变化,这可以解释为真空双折射与偶极磁场结构在偏振限制(绝热)半径处的综合效应。应用RVM使我们能够确定XRP的几何结构,并证实Her X-1中中子星(NS)的自由进动。两个明亮暂现源对RVM的偏离导致发现了一种非脉冲偏振辐射,该辐射很可能由吸积盘风散射产生。

英文摘要:

Radiation from X-ray pulsars (XRPs) was expected to be strongly linearly polarized owing to a large difference in their ordinary and extraordinary mode opacities. The launch of IXPE allowed us to check this prediction. IXPE observed a dozen X-ray pulsars, discovering pulse-phase dependent variation of the polarization degree (PD) and polarization angle (PA). Although the PD showed rather erratic profiles resembling flux pulse dependence, the PA in most cases showed smooth variations consistent with the rotating vector model (RVM), which can be interpreted as a combined effect of vacuum birefringence and dipole magnetic field structure at a polarization-limiting (adiabatic) radius. Application of the RVM allowed us to determine XRP geometry and to confirm the free precession of the NS in Her X-1. Deviations from RVM in two bright transients led to the discovery of an unpulsed polarized emission likely produced by scattering off the accretion disk wind.

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。

↑