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arXiv 1609.03356astro-ph.HEastro-ph.GA
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第谷超新星遗迹中巴尔末主导冲击的H $α$成像光谱学

H$α$ Imaging spectroscopy of Balmer-dominated shocks in Tycho's supernova remnant

Sladjana Knežević, Ronald Läsker, Glenn van de Ven, Joan Font, John C. Raymond, Parviz Ghavamian, John Beckman

摘要:

我们介绍了历史超新星遗迹第谷(SN 1572)激波阵面中窄H $α$分量的法布里-珀罗干涉观测。利用威廉·赫歇尔望远镜上的GH $α$ FaS(Galaxy H $α$ Fabry-Pérot Spectrometer),我们观测到大部分位于残骸东北部(NE)的激波阵面。$\sim$ 1 $^{\prime\prime}$的角分辨率和R $\sim$ 21 000的光谱分辨率以及大视场(3.4 $^{\prime}$ $\times$ 3.4 $^{\prime}$)的仪器允许我们测量窄H $α$ -同时在冲击波各个部分的73个单元中的谱线宽度,从而研究多种冲击波阵面中几种冲击波前兆的指示器条件与以前的研究相比,详细的空间分辨率的灯丝也使我们能够减轻可能的人为加宽的线从未解决的差分运动和投影。覆盖四分之一的残留物的壳,我们确认扩大的窄H $α$线超过其固有的宽度$\sim$ 20公里/秒,并报告它延伸到大部分的灯丝,不仅是以前研究的密集的“结g”。同样,我们确认并发现了广泛传播的中间线($\sim$ 150 km/s)排放的额外有力证据。我们的贝叶斯分析方法使我们能够量化这一中间成分的证据,以及在狭窄的线可能分裂。超热窄线宽指向一个额外的加热机制,在宇宙射线前体的形式,而中间组件,以前只定性报告为一个小的非高斯贡献的窄组件,揭示了广泛的中性前体。

英文摘要:

We present Fabry-Pérot interferometric observations of the narrow H$α$ component in the shock front of the historical supernova remnant Tycho (SN 1572). Using GH$α$FaS (Galaxy H$α$ Fabry-Pérot Spectrometer) on the William Herschel Telescope, we observed a great portion of the shock front in the northeastern (NE) region of the remnant. The angular resolution of $\sim$1$^{\prime\prime}$ and spectral resolving power of R$\sim$21 000 together with the large field-of-view (3.4$^{\prime}$ $\times$ 3.4$^{\prime}$) of the instrument allow us to measure the narrow H$α$-line width in 73 bins across individual parts of the shock simultaneously and thereby study the indicators of several shock precursors in a large variety of shock front conditions. Compared to previous studies, the detailed spatial resolution of the filament also allows us to mitigate possible artificial broadening of the line from unresolved differential motion and projection. Covering one quarter of the remnant's shell, we confirm the broadening of the narrow H$α$ line beyond its intrinsic width of $\sim$20 km/s and report it to extend over most of the filament, not only the previously investigated dense 'knot g'. Similarly, we confirm and find additional strong evidence for wide-spread intermediate-line ($\sim$150 km/s) emission. Our Bayesian analysis approach allows us to quantify the evidence for this intermediate component as well as a possible split in the narrow line. Suprathermal narrow line widths point toward an additional heating mechanism in the form of a cosmic-ray precursor, while the intermediate component, previously only qualitatively reported as a small non-Gaussian contribution to the narrow component, reveals a broad-neutral precursor.

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