“香肠”无线电遗迹的重新加速模型

IF 1.1 4区 物理与天体物理 Q3 ASTRONOMY & ASTROPHYSICS
Hyesung Kang
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引用次数: 6

摘要

香肠射电遗迹是CIZA J2242.8+5301星系团中的弧形射电结构,其观测到的性质可以通过在合并驱动激波下加速的相对论性电子的同步辐射来最好地理解。然而,仅采用原位注入的冲击加速度模型仍存在一些难以解释的问题。特别是,从观测到的射电光谱指数推断的马赫数M radio≈4.6,而从X射线观测估计的马赫数M X−ray≈2.7。为了解决这种差异,我们考虑了再加速模型,其中Ms≈3的激波带着预先存在的相对论性电子群扫过星系团内气体。我们发现在多频率下观测到的亮度分布对预先存在的电子的光谱形状有很强的限制。具有斜率为s≈4.1的幂律动量谱和截止洛伦兹因子γ e,c≈3−5×10⁴的模型可以相当好地再现观测到的香肠遗迹的无线电通量和综合无线电频谱的空间分布。簇内介质中这种相对论性电子的可能起源仍有待进一步研究。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
RE-ACCELERATION MODEL FOR THE `SAUSAGE` RADIO RELIC
The Sausage radio relic is the arc-like radio structure in the cluster CIZA J2242.8+5301, whose observed properties can be best understood by synchrotron emission from relativistic electrons accelerated at a merger-driven shock. However, there remain a few puzzles that cannot be explained by the shock acceleration model with only in-situ injection. In particular, the Mach number inferred from the observed radio spectral index, M radio ≈ 4.6, while the Mach number estimated from X-ray observations, M X−ray ≈ 2.7. In an attempt to resolve such a discrepancy, here we consider the re-acceleration model in which a shock of Ms ≈ 3 sweeps through the intracluster gas with a pre-existing population of relativistic electrons. We find that observed brightness profiles at multi frequencies provide strong constraints on the spectral shape of pre-existing electrons. The models with a power-law momentum spectrum with the slope, s ≈ 4.1, and the cutoff Lorentz factor, γ e,c ≈ 3−5×10⁴, can reproduce reasonably well the observed spatial profiles of radio fluxes and integrated radio spectrum of the Sausage relic. The possible origins of such relativistic electrons in the intracluster medium remain to be investigated further.
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来源期刊
Journal of the Korean Astronomical Society
Journal of the Korean Astronomical Society 地学天文-天文与天体物理
CiteScore
1.30
自引率
10.00%
发文量
0
审稿时长
>12 weeks
期刊介绍: JKAS is an international scientific journal publishing papers in all fields of astronomy and astrophysics. All manuscripts are subject to the scrutiny of referees. Manuscripts submitted to JKAS must comply with the ethics policy of JKAS. Six regular issues are published each year on February 28, April 30, June 30, August 31, October 31, and December 31. One year''s issues compose one volume.
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