爱因斯坦探针发现磁星EP J223759.5+531421
Einstein Probe discovery of the magnetar EP J223759.5+531421
- Institute of Space Sciences (ICE–CSIC)（空间科学研究所）
- Institut d’Estudis Espacials de Catalunya (IEEC)（加泰罗尼亚太空研究学院）
- INAF–Osservatorio Astronomico di Brera（意大利国家天体物理研究所布雷拉天文台）
- European Space Astronomy Centre (ESAC), ESA（欧洲空间局太空飞行中心）
- National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）
- School of Astronomy and Space Science, University of Chinese Academy of Sciences（中国科学院大学天文与空间科学学院）
- School of Astronomy and Space Science, Nanjing University（南京大学天文与空间科学学院）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
爱因斯坦探针发现新磁星EP J223759.5+531421，通过X射线脉冲和爆发确认其性质，并跟踪其早期爆发演化，展示了宽视场监测发现静默磁星的潜力。
AI中文摘要：
我们报告了由爱因斯坦探针宽视场X射线望远镜于2026年6月28日探测到的新的银河系磁星EP J223759.5+531421的发现及其早期爆发演化。利用爱因斯坦探针、XMM-牛顿、NuSTAR、SVOM和IXPE进行的后续观测揭示了周期P约6秒的相干X射线脉冲，以及平均周期导数Pdot约2.8×10^{-12}秒/秒。这些数值意味着标称的偶极磁场B_dip约2.6×10^{14}高斯，特征年龄tau_c约34千年，尽管结构化的计时残差表明可能存在扭矩变化。均方根脉冲分数在约7 keV以下约为20-25%，并在更高能量下降低。宽带光谱需要多个热成分和一个硬幂律尾。采用3.3千秒差距的距离，0.5-30 keV光度在第一个月内从1.2×10^{35}下降到5.7×10^{34}尔格/秒，同时推断的热发射面积减小。在此距离下，银河纬度b=-4.56度对应于银河平面下方约0.26千秒差距的高度，即使在极端自行速度下，也难以与简单中平面诞生场景下的标称特征年龄相协调。短X射线爆发独立证实了该源的磁星性质。GTC、Medicina和FAST分别未探测到近红外或射电对应体，极限星等K_s>21等，极限流量S_{1.25 GHz}<2.3微央。这些观测展示了爱因斯坦探针WXT监测的潜力，能够发现先前静默的银河系磁星，并从其最早观测阶段跟踪其爆发。
英文摘要：
We report the discovery and early outburst evolution of the new Galactic magnetar EP J223759.5+531421, detected by the Einstein Probe Wide-field X-ray Telescope on 2026 June 28. Follow-up observations with Einstein Probe, XMM--Newton, NuSTAR, SVOM, and IXPE revealed coherent X-ray pulsations at P ~ 6s and an average period derivative of Pdot ~ 2.8x10^{-12} s/s. These values imply a nominal polar dipolar magnetic field of B_dip ~ 2.6x10^{14} Gauss and a characteristic age of tau_c ~ 34 kyr, although the structured timing residuals suggest possible torque variability. The rms pulsed fraction is approximately 20-25% below ~7 keV and decreases at higher energies. The broadband spectra require multiple thermal components and a hard power-law tail. Adopting a distance of 3.3 kpc, the 0.5-30 keV luminosity declined from 1.2x10^{35} to 5.7x10^{34} erg/s during the first month, accompanied by a decrease in the inferred thermal-emitting areas. At this distance, the Galactic latitude b=-4.56 deg corresponds to a height of approximately 0.26 kpc below the Galactic plane, which is difficult to reconcile with the nominal characteristic age under a simple midplane-birth scenario even for an extreme proper motion velocity. Short X-ray bursts independently confirm the magnetar nature of the source. No near-infrared or radio counterpart were detected by GTC, Medicina or FAST, respectively, down to K_s>21 mag and S_{1.25 GHz} <2.3 microJy. These observations demonstrate the potential of the Einstein Probe WXT monitoring to uncover previously quiescent Galactic magnetars and follow their outbursts from their earliest observed stages.
