Toward the Understanding of the Physical Origin of Recombining Plasma in the Supernova Remnant IC 443
Toward the Understanding of the Physical Origin of Recombining Plasma in the Supernova Remnant IC 443
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DOI：
10.3847/1538-4357/aa9bdf
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发表时间：
2017-11
期刊：
影响因子：
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通讯作者：
Hideaki Matsumura;Takaaki Tanaka;H. Uchida;H. Okon;T. Tsuru
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文献类型：
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作者：
Hideaki Matsumura;Takaaki Tanaka;H. Uchida;H. Okon;T. Tsuru
我们进行了空间分辨光谱分析的X射线发射超新星遗迹（SNR）IC 443与朱雀。所有的光谱很好地再现了由碰撞电离平衡（CIE）和两个重组等离子体（RP）组件组成的模型。虽然先前的X射线研究在东北部地区发现了RP，但这是关于遗迹其他部分RP的第一份报告。电子温度，kTe，CIE组件，几乎是均匀的，在10.2千电子伏的剩余。CIE等离子体具有与太阳一致的金属丰度，并集中在残骸的边缘，这表明它是冲击星际介质的起源。两个RP组件具有不同的kTe：一个在0.16-0.28 keV的范围内，另一个在0.48-0.67 keV的范围内。这两个RP组件的电子温度下降向东南方向，在那里的SNR冲击是已知的分子云相互作用。我们还发现，低kTe RP高kTe RP组件的归一化比向东南方向增加。这两个结果表明，在东南部地区的X射线发射等离子体显着冷却的一些机制。其中一个合理的冷却机制是热等离子体和分子云之间的热传导。如果冷却进行得比等离子体的复合时间尺度更快，则相同的机制也可以解释复合等离子体。
We perform a spatially resolved spectroscopic analysis of X-ray emission from the supernova remnant (SNR) IC 443 with Suzaku. All of the spectra are well reproduced by a model consisting of a collisional ionization equilibrium (CIE) and two recombining plasma (RP) components. Although previous X-ray studies found an RP in the northeastern region, this is the first report on RPs in the other parts of the remnant. The electron temperature, kTe, of the CIE component is almost uniform at ∼0.2 keV across the remnant. The CIE plasma has metal abundances consistent with solar and is concentrated toward the rim of the remnant, suggesting that it is of shocked interstellar medium origin. The two RP components have different kTe: one in the range of 0.16–0.28 keV and the other in the range of 0.48–0.67 keV. The electron temperatures of both RP components decrease toward the southeast, where the SNR shock is known to be interacting with a molecular cloud. We also find the normalization ratio of the lower-kTe RP to higher-kTe RP components increases toward the southeast. Both results suggest the X-ray emitting plasma in the southeastern region is significantly cooled by some mechanism. One of the plausible cooling mechanisms is a thermal conduction between the hot plasma and the molecular cloud. If the cooling proceeds faster than the recombination timescale of the plasma, the same mechanism can account for the recombining plasma as well.