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arXiv 2007.00696astro-ph.GAastro-ph.HE
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宇宙射线在星系外流早期阶段的作用

Role of cosmic rays in the early stages of galactic outflows

Ranita Jana, Siddhartha Gupta, Biman B. Nath

摘要:

利用一个理想化的装置,我们研究了宇宙射线(CR)在晕质量为$10^{8}$,$10^{11}$和$10^{12}$ $M_\odot$的星系外流早期阶段的动力学作用。外流是从银河系盘的中心区域发射的,在那里我们考虑了三种不同的恒星形成率($0.1$,$1$和$10$ $M_{\odot}$ yr $^{-1}$)在$50$ Myr的动力学时标。我们确定了气体的温度分布,发现压缩比可以降低冲击气体的温度,这与以前的结果是一致的。然而,我们表明,CR没有任何显着的影响上的流出的质量负荷。我们发现,CRs可以减少流出的大小,这与以前声称的有效的动力学影响的CRs相矛盾,但是,它是与早期的宇宙射线驱动的爆炸波以及恒星风的理论模型是一致的。我们讨论了我们的结果对CR注射处方的依赖性,并将其与早期研究进行了比较。我们的结论是,在银河系外流的早期阶段,CR的动力学作用是不重要的。

英文摘要:

Using an idealized set-up, we investigate the dynamical role of cosmic rays (CRs) in the early stages of galactic outflows for galaxies of halo masses $10^{8}$, $10^{11}$ and $10^{12}$ $M_\odot$. The outflow is launched from a central region in the galactic disk where we consider three different constant star formation rates ($0.1$, $1$, and $10$ $M_{\odot}$ yr$^{-1}$) over a dynamical timescale of $50$ Myr. We determine the temperature distribution of the gas and find that CRs can reduce the temperature of the shocked gas, which is consistent with previous results. However, we show that CRs do not have any noticeable effect on the mass loading by the outflow. We find that CRs can reduce the size of the outflow, which contradicts previous claims of efficient dynamical impact of CRs; however, it is consistent with earlier theoretical models of cosmic ray driven blastwave as well as stellar wind. We discuss the dependence of our results on CR injection prescriptions and compare them with earlier studies. We conclude that in the early stages of galactic outflows the dynamical role of CRs is not important.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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