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arXiv 2406.08561astro-ph.GA
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恒星形成星系风的理论与观测

Theory and Observation of Winds from Star-Forming Galaxies

Todd A. Thompson, Timothy M. Heckman

AI总结:

本文综述恒星形成星系风的驱动机制与观测属性,分析超新星等因素的作用,指出冷气体加速等未解问题与观测空白,提出需结合模拟与观测推进相关研究。

摘要:

星系风塑造着星系的恒星、气体与金属含量。为量化其影响,我们必须理解其物理机制。本文综述了潜在的风驱动机制与观测到的风属性,重点关注温电离气体与发射X射线的热气体。结合观测结果,我们分析了超新星(SNe)、宇宙射线、辐射压与磁场的能量和动量注入作用:(1)冷/温气体的发射线与吸收线测量是我们研究星系外流的最佳物理诊断工具。(2)尚未解决的关键问题是如何将冷气体加速到观测到的高速度。尽管尚无任何一种机制存在确凿证据,但观测到的动量、能量与质量负载预算与理论吻合良好。(3)一种模型认为恒星形成提供约$L/c$的作用力(其中$L$为光度),推动冷气体脱离星系引力势,该模型与现有数据吻合较好,其风功率约为超新星提供功率的0.1倍。(4)极热的X射线发射相可能是主要驱动因素之一(或是最主要的驱动因素),热相与较冷相之间的动量与能量交换对气体动力学至关重要。(5)我们的观测认知空白包括热气体运动学,以及通过紫外吸收线探测的外流的尺度与结构。我们需要开展模拟以更全面地理解混合过程、云-辐射相互作用、云-宇宙射线相互作用、云-热风相互作用、星团的集体效应,以及分布型与聚集型超新星的作用。观测工作应在风数据中寻找能为特定机制提供证据的次级关联,并将光谱观测与理论得出的柱密度-速度结果进行对比。

英文摘要:

Galactic winds shape the stellar, gas, and metal content of galaxies. To quantify their impact, we must understand their physics. We review potential wind-driving mechanisms and observed wind properties, with a focus on the warm ionized and hot X-ray-emitting gas. Energy and momentum injection by supernovae (SNe), cosmic rays, radiation pressure, and magnetic fields are considered in the light of observations: (1) Emission and absorption line measurements of cool/warm gas provide our best physical diagnostics of galactic outflows. (2) The critical unsolved problem is how to accelerate cool gas to the high velocities observed. Although conclusive evidence for no one mechanism exists, the momentum, energy, and mass-loading budgets observed compare well with theory. (3) A model where star formation provides a force $\sim L/c$, where $L$ is the bolometric luminosity, and cool gas is pushed out of the galaxy's gravitational potential, compares well with available data. The wind power is $\sim0.1$ that provided by SNe. (4) The very hot X-ray emitting phase, may be a (or the) prime mover. Momentum and energy exchange between the hot and cooler phases is critical to the gas dynamics. (5) Gaps in our observational knowledge include the hot gas kinematics and the size and structure of the outflows probed with UV absorption lines. Simulations are needed to more fully understand mixing, cloud-radiation, cloud-cosmic ray, and cloud-hot wind interactions, the collective effects of star clusters, and both distributed and clustered SNe. Observational works should seek secondary correlations in the wind data that provide evidence for specific mechanisms and compare spectroscopy with the column density-velocity results from theory.

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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