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arXiv 0906.4937astro-ph.GAastro-ph.HE
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一颗可能的超新星残骸位于银河系盘上方

A Possible Supernova Remnant high above the Galactic Disk

David B. Henley, Robin L. Shelton

摘要:

我们提出了在$l \approx 247\degr$,$b \approx -64\degr$的ROSAT全天巡天1/4 keV地图中的亮弧的三个朱雀观测的分析。特别是,我们已经测试的假设,弧是边缘的泡沫吹一个平面外的超新星。一个指向靠近弧的最亮部分,一个指向假设气泡的内部,一个指向气泡的外部。我们拟合的光谱模型产生的一维流体动力学模拟的面外超新星遗迹(SNRs)的光谱。光谱和弧($\mathrm{radius} \approx 5\degr$)的大小可以用一个模型合理地解释,在这个模型中,弧是位于盘上方$\sim$ 1- 2千秒差距的$\sim$ 10万年前的SNR的亮边。如果X射线发射气体的金属丰度为$\sim$ 1/3太阳能,则模型与观测之间的一致性可以得到改善,这是合理的,因为隔离某些金属的尘埃不太可能在SNR的寿命内被破坏。弧的宽度比我们的SNR模型预测的要大;这种差异也可以在船帆座SNR中看到,可能是由于我们模拟的一维性质。如果弧确实是面外SNR的边缘,这项工作支持面外超新星有助于加热晕中的$\sim$百万度气体的想法。

英文摘要:

We present the analysis of three Suzaku observations of a bright arc in the ROSAT All-Sky Survey 1/4 keV maps at $l \approx 247\degr$, $b \approx -64\degr$. In particular, we have tested the hypothesis that the arc is the edge of a bubble blown by an extraplanar supernova. One pointing direction is near the brightest part of the arc, one is toward the interior of the hypothesized bubble, and one is toward the bubble exterior. We fit spectral models generated from 1-D hydrodynamical simulations of extraplanar supernova remnants (SNRs) to the spectra. The spectra and the size of the arc ($\mathrm{radius} \approx 5\degr$) are reasonably well explained by a model in which the arc is the bright edge of a $\sim$100,000-yr old SNR located $\sim$1--2 kpc above the disk. The agreement between the model and the observations can be improved if the metallicity of the X-ray--emitting gas is $\sim$1/3 solar, which is plausible, as the dust which sequesters some metals is unlikely to have been destroyed in the lifetime of the SNR. The width of the arc is larger than that predicted by our SNR model; this discrepancy is also seen with the Vela SNR, and may be due to the 1-D nature of our simulations. If the arc is indeed the edge of an extraplanar SNR, this work supports the idea that extraplanar supernovae contribute to the heating of the $\sim$million-degree gas in the halo.

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