论文标题
从XMMU J053108.3-690923观察到的快速耀斑，由Erosita：大型麦哲伦云中的超级巨大快速X射线瞬变
Fast flaring observed from XMMU J053108.3-690923 by eROSITA: a supergiant fast X-ray transient in the Large Magellanic Cloud
论文作者
论文摘要
超级巨型快速X射线瞬变（SFXTS）是一类超级巨型X射线二进制（HMXB）系统，其特征在于X射线域中的极端可变性。在当前模型中，这主要归因于恒星风的块状性质以及涉及中子星的自旋和磁场的门控机制。我们在大麦芽云中研究了Supergiant HMXB XMMU J053108.3-690923的X射线特性，以了解其性质。我们对XMMU J053108.3-690923的Erosita和XMM-Newton数据进行了详细的时间和光谱分析。我们确认了以前对源头报道的推定脉动，以高度信心向来源报道，证明了其与超级伴侣的轨道中的中子星的性质。我们以Erosita光曲线中看到的耀斑形式识别来源的极度变化性质。源通量表现出超过三个数量级的总动态范围，这证实了它作为SFXT的性质，并且是我们银河系以外的HMXB的第一个直接证据，在我们的星系外表现出非常高的发光性范围以及快速燃烧的行为。在耀斑的间隔内，我们检测到硬度比在耀斑峰值期间达到其最小值的硬度比的变化，此后不久就会急剧增加。在峰值和非漏斗间隔进行的光谱分析的结果也支持了这一点。这种情况与XMMU J053108.3-690923的超级风中存在致密结构一致，其中块状培养基在耀斑的峰值上被照相，导致光电吸收的下降。此外，我们提供了假设自旋平衡条件的介质和中子恒星的磁场的块状估计值。
Supergiant fast X-ray transients (SFXTs) are a peculiar class of supergiant high-mass X-ray binary (HMXB) systems characterised by extreme variability in the X-ray domain. In current models, this is mainly attributed to the clumpy nature of the stellar wind coupled with gating mechanisms involving the spin and magnetic field of the neutron star. We studied the X-ray properties of the supergiant HMXB XMMU J053108.3-690923 in the Large Magellanic Cloud to understand its nature. We performed a detailed temporal and spectral analysis of the eROSITA and XMM-Newton data of XMMU J053108.3-690923. We confirm the putative pulsations previously reported for the source with high confidence, certifying its nature as a neutron star in orbit with a supergiant companion. We identify the extremely variable nature of the source in the form of flares seen in the eROSITA light curves. The source flux exhibits a total dynamic range of more than three orders of magnitude, which confirms its nature as an SFXT, and is the first such direct evidence from a HMXB outside our Galaxy exhibiting a very high dynamic range in luminosity as well as a fast flaring behaviour. We detect changes in the hardness ratio during the flaring intervals where the hardness ratio reaches its minimum during the peak of the flare and increases steeply shortly afterwards. This is also supported by the results of the spectral analysis carried out at the peak and off-flare intervals. This scenario is consistent with the presence of dense structures in the supergiant wind of XMMU J053108.3-690923 where the clumpy medium becomes photoionised at the peak of the flare leading to a drop in the photo-electric absorption. Further, we provide an estimate of the clumpiness of the medium and the magnetic field of the neutron star assuming a spin equilibrium condition.
