标题： BL LAC型耀变体1ES 0229+200的X射线偏振 显示英文标题

标题： X-ray Polarization of the BL Lac Type Blazar 1ES 0229+200

摘要： 我们展示了来自耀变体1ES 0229+200的$2-8 \thinspace \mathrm{keV}$带偏振测量数据，这是首个由成像X射线偏振探测器（IXPE）观测到的极端高同步峰源。 通过结合间隔约两周的两次曝光，我们利用IXPE和XMM-Newton联合观测的光谱偏振拟合发现偏振度为$\Pi_{X} = 17.9 \pm 2.8 \%$，电矢量位置角为$\psi_X = 25.0 \pm 4.6^{\circ}$。 在短时间尺度（数小时）或长时间尺度（数天）上均未发现偏振度或角度有显著随能量或时间变化的证据。 光学波段的同期偏振度比之低$>$$\times$，使1ES 0229+200成为迄今为止观测到的偏振色变最强烈的耀变体。 相比光学波段，这种高X射线偏振进一步支持了高同步峰耀变体的X射线发射源自冲击加速的能量分层电子群体，但与许多试图重现1ES 0229+200能谱能量分布的近期建模工作相矛盾，这些模型将极高的同步辐射和康普顿峰值归因于强湍动磁场附近的Fermi加速效应。 显示英文摘要

摘要： We present polarization measurements in the $2-8 \thinspace \mathrm{keV}$ band from blazar 1ES 0229+200, the first extreme high synchrotron peaked source to be observed by the Imaging X-ray Polarimetry Explorer (IXPE). Combining two exposures separated by about two weeks, we find the degree of polarization to be $\Pi_{X} = 17.9 \pm 2.8 \%$ at an electric-vector position angle $\psi_X = 25.0 \pm 4.6^{\circ}$ using a spectropolarimetric fit from joint IXPE and XMM-Newton observations. There is no evidence for the polarization degree or angle varying significantly with energy or time on both short time scales (hours) or longer time scales (days). The contemporaneous polarization degree at optical wavelengths was $>$7$\times$ lower, making 1ES 0229+200 the most strongly chromatic blazar yet observed. This high X-ray polarization compared to the optical provides further support that X-ray emission in high-peaked blazars originates in shock-accelerated, energy-stratified electron populations, but is in tension with many recent modeling efforts attempting to reproduce the spectral energy distribution of 1ES 0229+200 which attribute the extremely high energy synchrotron and Compton peaks to Fermi acceleration in the vicinity of strongly turbulent magnetic fields.