论文标题
矮星系中超新星的宇宙射线反馈
Cosmic ray feedback from supernovae in dwarf galaxies
论文作者
论文摘要
矮星系中重型含量的调节是一个长期存在的问题。超新星（SNE）应该通过去除星系中的重要气体来形成大规模银河风中发挥关键作用。 SNE是非热颗粒的有效加速器，即所谓的宇宙射线（CRS），可以实质上改变气体和条件的动力学，形成大型银河风。我们研究了SNE的CR注射如何影响矮星系中的恒星形成和大规模风的形成，以及它是否可以产生星系恒星形成率（SFR）以及更接近观察结果的风质。我们在高分辨率（9 PC）的矮星系（9 PC）上运行了CR磁动力学模拟，并带有自适应网状细化代码公羊。圆盘星系嵌入为$ 10^{10} $和$ 10^{11} \，\ rm m _ {\ odot} $的隔离光环中，并且CRS由SNE注入。我们包括各种扩散系数，CR辐射损耗和CR流媒体的CR各向同性和各向异性扩散。将CR能量注入到星际培养基中的最高气体密度使SFR降低了2-3倍。随着CR扩散，质量流出速率明显更高，对于较高的扩散系数，大小的尺寸尺寸较高。没有扩散和流媒体，CRS在产生风方面效率低下。仅CR流式流可以形成风，但太弱，无法匹配观测。银河风的形成很大程度上取决于扩散系数：对于低系数，Cr能量限制在CR能量损失最高和更高系数的高密度区域，并且使CRS从密集的气体中更有效地泄漏出来，从而产生强风。 CR扩散会导致比没有CRS更冷和更密集的风，并且使流出速率和质量负载因子更接近观察。
The regulation of the baryonic content in dwarf galaxies is a long-standing problem. Supernovae (SNe) are supposed to play a key role in forming large-scale galactic winds by removing important amounts of gas from galaxies. SNe are efficient accelerators of non-thermal particles, so-called cosmic rays (CRs), which can substantially modify the dynamics of the gas and conditions to form large-scale galactic winds. We investigate how CR injection by SNe impacts the star formation and the formation of large-scale winds in dwarf galaxies, and whether it can produce galaxy star-formation rates (SFR) and wind properties closer to observations. We ran CR magneto-hydrodynamical simulations of dwarf galaxies at high resolution (9 pc) with the adaptive mesh refinement code ramses. Disc galaxies are embedded in isolated halos of mass of $10^{10}$ and $10^{11} \, \rm M_{\odot}$, and CRs are injected by SNe. We included CR isotropic and anisotropic diffusion with various diffusion coefficients, CR radiative losses, and CR streaming. The injection of CR energy into the interstellar medium smooths out the highest gas densities, which reduces the SFR by a factor of 2-3. Mass outflow rates are significantly greater with CR diffusion, by 2 orders of magnitudes for the higher diffusion coefficients. Without diffusion and streaming, CRs are inefficient at generating winds. CR streaming alone allows for the formation of winds but which are too weak to match observations. The formation of galactic winds strongly depends on the diffusion coefficient: for low coefficients, CR energy stays confined in high density regions where CR energy losses are highest, and higher coefficients, which allow for a more efficient leaking of CRs out of dense gas, produce stronger winds. CR diffusion leads to colder and denser winds than without CRs, and brings outflow rates and mass loading factors much closer to observations.
