当前位置: X-MOL 学术Mon. Not. R. Astron. Soc. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Effects of Different Cosmic Ray Transport Models on Galaxy Formation
Monthly Notices of the Royal Astronomical Society ( IF 4.7 ) Pub Date : 2020-11-28 , DOI: 10.1093/mnras/staa3692
Philip F Hopkins 1 , T K Chan 2 , Jonathan Squire 3 , Eliot Quataert 4 , Suoqing Ji 1 , Dušan Kereš 2 , Claude-André Faucher-Giguére 5
Affiliation  

Cosmic rays (CRs) with ~GeV energies can contribute significantly to the energy and pressure budget in the interstellar, circumgalactic, and intergalactic medium (ISM, CGM, IGM). Recent cosmological simulations have begun to explore these effects, but almost all studies have been restricted to simplified models with constant CR diffusivity and/or streaming speeds. Physical models of CR propagation/scattering via extrinsic turbulence and self-excited waves predict transport coefficients which are complicated functions of local plasma properties. In a companion paper, we consider a wide range of observational constraints to identify proposed physically-motivated cosmic-ray propagation scalings which satisfy both detailed Milky Way (MW) and extra-galactic $\gamma$-ray constraints. Here, we compare the effects of these models relative to simpler 'diffusion+streaming' models on galaxy and CGM properties at dwarf through MW mass scales. The physical models predict large local variations in CR diffusivity, with median diffusivity increasing with galacto-centric radii and decreasing with galaxy mass and redshift. These effects lead to a more rapid dropoff of CR energy density in the CGM (compared to simpler models), in turn producing weaker effects of CRs on galaxy star formation rates (SFRs), CGM absorption profiles and galactic outflows. The predictions of the more physical CR models tend to lie 'in between' models which ignore CRs entirely and models which treat CRs with constant diffusivity.

中文翻译:

不同宇宙射线传输模型对星系形成的影响

具有 ~GeV 能量的宇宙射线 (CRs) 可以对星际、环星系和星际介质(ISM、CGM、IGM)中的能量和压力预算做出重大贡献。最近的宇宙学模拟已经开始探索这些影响,但几乎所有的研究都仅限于具有恒定 CR 扩散率和/或流速度的简化模型。通过外在湍流和自激波的 CR 传播/散射物理模型预测传输系数,这是局部等离子体特性的复杂函数。在一篇配套论文中,我们考虑了广泛的观测约束,以确定提出的物理驱动的宇宙射线传播比例,满足详细的银河系 (MW) 和星系外 $\gamma$ 射线约束。在这里,我们比较了这些模型相对于更简单的 ' 通过 MW 质量尺度的矮星系和 CGM 特性的扩散+流模型。物理模型预测 CR 扩散率的局部变化很大,中值扩散率随着以半乳为中心的半径增加而随着星系质量和红移而减少。这些效应导致 CGM 中 CR 能量密度的下降更快(与更简单的模型相比),反过来产生 CR 对星系恒星形成率 (SFR)、CGM 吸收剖面和星系外流的较弱影响。更物理的 CR 模型的预测往往介于完全忽略 CR 的模型和以恒定扩散率处理 CR 的模型之间。中值扩散率随着以半乳为中心的半径增加而随着星系质量和红移而减少。这些效应导致 CGM 中 CR 能量密度的下降更快(与更简单的模型相比),反过来产生 CR 对星系恒星形成率 (SFR)、CGM 吸收剖面和星系外流的较弱影响。更物理的 CR 模型的预测往往介于完全忽略 CR 的模型和以恒定扩散率处理 CR 的模型之间。中值扩散率随着以半乳为中心的半径增加而随着星系质量和红移而减少。这些效应导致 CGM 中 CR 能量密度的下降更快(与更简单的模型相比),反过来产生 CR 对星系恒星形成率 (SFR)、CGM 吸收剖面和星系外流的较弱影响。更物理的 CR 模型的预测往往介于完全忽略 CR 的模型和以恒定扩散率处理 CR 的模型之间。
更新日期:2020-11-28
down
wechat
bug