标题： X射线脉冲星模型的超亮X射线脉冲星光谱分析 显示英文标题

标题： Spectral analysis of ultraluminous X-ray pulsars with models of X-ray pulsars

摘要： 一些超亮X射线（ULX）源被证实是吸积中子星，因为它们表现出从约1-30秒范围内的相干X射线脉动。 虽然最初认为它们可能包含中等质量黑洞，但ULXs后来被认识到是一个多样化的物体类别，包括ULX脉冲星。 这些脉冲星需要专门的模型来解释其独特的吸积物理过程，与用于银河系黑洞双星的模型不同。 所有银河系吸积X射线脉冲星（包括大麦哲伦星云和小麦哲伦星云中的源）的X射线光谱主要由高能截止幂律主导，其中一些源显示出软过量、一些发射线、回旋吸收特征等。 在本研究中，我们利用XMM-Newton和NuSTAR的同时观测对五个ULX脉冲星的宽波段X射线光谱进行了全面分析，并表明它们的X射线光谱可以有效地用类似于用于本地吸积驱动X射线脉冲星的光谱模型来描述。 在所有源中都检测到了软过量，这也与具有低吸收柱密度的本地X射线脉冲星一致。 我们对这些源的铁K-alpha发射线的存在有边缘检测或低上限，这是ULX脉冲星与本地吸积X射线脉冲星的一个关键区别。 我们讨论了这一结果对ULX脉冲星的双星伴星性质和吸积机制的含义。 显示英文摘要

摘要： A fraction of the Ultra Luminous X-ray (ULX) sources are known to be accreting neutron stars as they show coherent X-ray pulsations with pulse periods ranging from ~1-30 seconds. While initially thought to host intermediate-mass black holes, ULXs have since been recognized as a diverse class of objects, including ULX pulsars. These pulsars require models specifically tailored to account for their unique accretion physics, distinct from those used for Galactic black hole binaries. The X-ray spectra of all Galactic accreting X-ray pulsars (including sources in the Magellanic Clouds) are dominated by a high energy cut-off power-law and some of the sources show a soft excess, some emission lines, cyclotron absorption features, etc. In this work, we undertake a comprehensive analysis of the broadband X-ray spectra of five ULX pulsars using simultaneous XMM-Newton and NuSTAR observations and show that their X-ray spectra can be effectively described by spectral models, similar to those used for the local accretion-powered X-ray pulsars. A soft excess is detected in all the sources which is also consistent with the local X-ray pulsars that have low absorption column density. We have marginal detection or low upper limit on the presence of the iron K-alpha emission line from these sources, which is a key difference of the ULX pulsars with the local accreting X-ray pulsars. We discuss the implication of this on the nature of the binary companion and the accretion mechanism in the ULX pulsars.