论文标题
检测中子星M51 ULX-8的125.5天光学周期调制
Detection of 125.5-day Optical Periodic Modulation of the Neutron Star M51 ULX-8
论文作者
论文摘要
在光波长中研究超充血的X射线源（ULX）提供了有关X射线二元系统的吸积机制和进化过程的重要线索。在这项研究中，针对基于Chandra和Hubble Space望远镜的高级天文统计，鉴定出了三个（C1，C2和C3）可能的光学对应物，用于著名的中子星（NS）候选M51 ULX-8，HST）观察值以及Gaia光源分解。确定C3的光学周期性调制为125.5天，幅度为0.14，有证据表明使用一年（2016-2017）34 HST ACS（用于监视的高级摄像机）/WFC（宽场摄像机）观察结果。此外，令人惊讶的是，观察到的C3的光通量表现出双模式分布。这可能意味着ULX-8的光学和X射线通量变化之间存在可能的相关性。文献中经常提到的有关光学发射性质和光学超级轨道时期的可能场景。最可能的情况是光发射可能源自ULX-8的积聚磁盘。
Studying Ultraluminous X-ray sources (ULXs) in the optical wavelengths provides important clues about the accretion mechanisms and the evolutionary processes of X-ray binary systems. In this study, three (C1, C2, and C3) possible optical counterparts were identified for well-known neutron star (NS) candidate M51 ULX-8 through advanced astrometry based on the Chandra and Hubble Space Telescope, HST) observations, as well as the GAIA optical source catalogue. Optical periodic modulation of 125.5 days with an amplitude of 0.14 magnitude was determined for C3 which has evidence to represent the optical nature of ULX-8 using one-year (2016-2017) 34 HST ACS (Advanced Camera for Surveys)/WFC (Wide Field Camera) observations. Moreover, surprisingly, the observed optical fluxes of C3 exhibit a bi-modal distribution. This could mean that there is a possible correlation between the optical and the X-ray flux variabilities of the ULX-8. The possible scenarios which are frequently mentioned in the literature proposed for the nature of optical emission and optical super-orbital period. The most probable scenario is that the optical emission could have originated from the accretion disk of the ULX-8.
