arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节(Veterans Day),12 日无更新
arXiv 1802.03538astro-ph.HE
收藏

从Milky Way星系可能的氢气密度分布约束晕的大小

Constraining the halo size from possible density profiles of hydrogen gas of Milky Way Galaxy

Sayan Biswas, Nayantara Gupta

摘要:

银河系磁场和次级宇宙射线(如$^{10}$铍、硼、反质子)是研究次级宇宙线在银河系中传播的重要组成部分。GMF的真实模型是基于各种银河系和河外射电源的法拉第旋转测量和CR轻子在射频范围内的同步辐射,从而提供晕高度的信息。另一方面,扩散系数和晕高度也由$^{10}$ Be/ $^{9}$ Be和B/C比值估算。此外,星际介质(ISM)气体组分的密度分布也起着重要的作用,因为由于初级CRs与ISM气体组分的相互作用而产生次级CRs。我们的研究主要考虑氢气的分子、原子和电离成分。最近的观测和流体动力学模拟提供了银河系中氢气密度分布的新形式。在\texttt{DRAGON}代码中,我们已经实现了我们选择的密度分布,基于无线电,X射线和$γ$射线波段的实际观测,以及星际氢气的流体动力学模拟,以研究适合所观察到的CR光谱所需的晕的高度变化。我们的研究结果表明,晕的高度($z_{t}$)在2至6 kpc的范围内变化的密度分布在我们的工作中考虑。

英文摘要:

Galactic magnetic field (GMF) and secondary cosmic rays (CRs) (e.g. $^{10}$beryllium, boron, antiproton) are important components to understand the propagation of CRs in the Milky Way Galaxy. Realistic modeling of GMF is based on the Faraday rotation measurements of various Galactic and extragalactic radio sources and synchrotron emission from CR leptons in the radio frequency range, thereby providing information of halo height. On the other hand, diffusion coefficient and halo height are also estimated from the $^{10}$Be/$^{9}$Be and B/C ratios. Moreover, density distribution of gaseous components of interstellar medium (ISM) also plays an important role as secondary CRs are produced due to interaction of primary CRs with the gaseous components of ISM. We consider mainly molecular, atomic, and ionized components of hydrogen gas for our study. Recent observations and hydrodynamical simulations provide new forms of density profiles of hydrogen gas in Milky Way Galaxy. In the \texttt{DRAGON} code, we have implemented our chosen density profiles, based on realistic observations in radio, X-ray and $γ$-ray wavebands, and hydrodynamical simulations of interstellar hydrogen gas to study the variation in the height of the halo required to fit the observed CR spectra. Our results show the halo height ($z_{t}$) varies in the range of 2 to 6 kpc for the density profiles considered in our work.

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。

↑