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arXiv 2007.11593astro-ph.HE
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用XMM-牛顿法研究W49B等离子体的空间分辨

Spatially-Resolved Study of Recombining Plasma in W49B Using XMM-Newton

Tyler Holland-Ashford, Laura A. Lopez, Katie Auchettl

摘要:

W 49 B是迄今为止最年轻的展示重组等离子体的SNR。这种过电离的两种流行理论是通过绝热膨胀或通过与邻近较冷介质的热传导快速冷却。为了限制W 49 B中重组等离子体的起源,我们对46个区域的深XMM-牛顿数据进行了空间分辨光谱研究。我们采用了一个3组件模型(一个ISM和两个喷出物组件),我们发现,重组等离子体是存在于整个SNR,随着从东到西的过度电离。后一个结果与前人的研究结果一致,我们把西部的过电离现象归因于绝热膨胀。然而,我们的研究结果对比了这些先前的工作,因为我们在东部也发现了过度电离的证据。由于SNR与分子物质相互作用,我们研究了热传导作为快速冷却起源的可能性。我们表明,估计的时间尺度的基础上,这是可能的,小规模的热传导,通过蒸发的cloudos,密集的云与0.1-1.0 pc的规模可以解释所观察到的过度电离在东部。

英文摘要:

W49B is the youngest SNR to date that exhibits recombining plasma. The two prevailing theories of this overionization are rapid cooling via adiabatic expansion or through thermal conduction with an adjacent cooler medium. To constrain the origin of the recombining plasma in W49B, we perform a spatially-resolved spectroscopic study of deep XMM-Newton data across 46 regions. We adopt a 3-component model (with one ISM and two ejecta components), and we find that recombining plasma is present throughout the entire SNR, with increasing overionization from east to west. The latter result is consistent with previous studies, and we attribute the overionization in the west to adiabatic expansion. However, our findings contrast these prior works as we find evidence of overionization in the east as well. As the SNR is interacting with molecular material there, we investigate the plausibility of thermal conduction as the origin of the rapid cooling. We show that based on the estimated timescales, it is possible that small-scale thermal conduction through evaporation of clumpy, dense clouds with a scale of 0.1-1.0 pc can explain the observed overionization in the east.

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