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arXiv 2004.07963astro-ph.HEastro-ph.SR
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反常X射线脉冲星4U 0142+61的磁白矮星吸积模型

A magnetic white-dwarf accretion model for the anomalous X-ray pulsar 4U 0142+61

Sarah V. Borges, Claudia V. Rodrigues, Jaziel G. Coelho, Manuel Malheiro, Manuel Castro

摘要:

异常X射线脉冲星(AXP)4U 0142+61的静态发射涵盖了从射电到硬X射线的广泛能量范围。特别是,该对象是唯一的软伽马射线中继器(SGR)和AXP中同时呈现中红外发射和脉冲光发射。尽管有许多命题来解释这种大范围的发射,但仍然缺乏一个再现所有观测结果的命题。填补这一空白,我们提出了一个模型来重现静态光谱能量分布的4U 0142+61从中红外到硬X射线使用合理的物理组件和参数。我们认为持续辐射来自于被碎片盘包围的磁吸积白矮星(WD)。该模型假设:(i)硬X射线是由吸积柱激波后区域的韧致辐射产生的;(ii)软X射线是由WD表面的热点产生的;(iii)光学和红外辐射是由光学厚尘埃盘、WD光球和激波后区域辐射的尾部引起的。在这种情况下,拟合的模型参数表明,4U 0142+61拥有一个快速旋转的磁性近rasekhar WD,这是非常热,因此年轻。这样一个WD可能是两个规模较小的WD合并的最新结果。在这种情况下,4U 0142+61可以演化为超新星Ia,因此可以提供这些重要天体物理事件起源的线索。此外,我们还提出了一个新的估计4U 0142+61的距离,3.78(误差:+0.12 / -0.18千秒差距),根据测量的氢柱密度和新的星际灭绝3D地图。

英文摘要:

The quiescent emission of the anomalous X-ray pulsar (AXP) 4U 0142+61 extends over a broad range of energy, from radio up to hard X-rays. In particular, this object is unique among soft gamma-ray repeaters (SGRs) and AXPs in presenting simultaneously mid-infrared emission and pulsed optical emission. In spite of the many propositions to explain this wide range of emission, it still lacks one that reproduces all the observations. Filling this gap, we present a model to reproduce the quiescent spectral energy distribution of 4U 0142+61 from mid-infrared up to hard X-rays using plausible physical components and parameters. We propose that the persistent emission comes from a magnetic accreting white dwarf (WD) surrounded by a debris disk. This model assumes that: (i) the hard X-rays are due to the bremsstrahlung emission from the post-shock region of the accretion column; (ii) the soft X-rays are originated by hot spots on the WD surface; and (iii) the optical and infrared emissions are caused by an optically thick dusty disk, the WD photosphere, and the tail of the postshock region emission. In this scenario, the fitted model parameters indicate that 4U 0142+61 harbors a fast-rotator magnetic near-Chandrasekhar WD, which is very hot and hence young. Such a WD can be the recent outcome of a merger of two less massive WDs. In this case, 4U 0142+61 can evolve to an SN Ia and hence can give hints of the origin of these important astrophysical events. Additionally, we also present a new estimate of 4U 0142+61 distance, 3.78 (errors: +0.12 / -0.18 kpc), based on the measured Hydrogen column density and new interstellar extinction 3D maps.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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