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Baryon Cycles in the Biggest Galaxies

最大星系中的重子循环

基本信息

批准号：
2106575
负责人：
G. Mark Voit
金额：
$ 51.36万
依托单位：
Michigan State University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-09-01 至 2024-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2106575&HistoricalAwards=false
关键词：
Baryon Cycles Biggest Galaxies

项目摘要

In order to fully understand galaxy evolution one must identify the major processes that shape them over time. One such process is the “baryon cycle”, analogous to the Water and Carbon cycles on Earth, whereby gas cycles between a galaxy’s interstellar (ISM) and circum-galactic media (CGM) as determined by various heating (e.g., supernovae and radio jets) and cooling mechanisms, in the process forming a complex and dynamic galactic “atmosphere”. The details of this process regulates gas flows into or out of the galaxy and thus star formation and chemical enrichment of a galaxy’s environment. This research will use detailed numerical simulations to understand the dynamics of galactic atmospheres. The investigators will support public education through a dual-purpose website: one featuring visualizations of computer simulations and a second featuring interactive e-text to introduce students to the physics of galaxy atmospheres. One postdoc will be supported.This research will investigate the dynamics of galaxy atmospheres – i.e., the combined ISM and CGM – by determining its relaxed quasi-hydrostatic equilibrium states and the departures from these states due to energy input (e.g., supernovae and active galactic nuclei) and mass accretion. Three broad groups of numerical simulations will attempt to: (1) better understand how the condensation and subsequent “precipitation” of cool gas from the CGM to the ISM depends on (e.g.) the local gas turbulence, large-scale entropy gradients, perturbations, buoyancy, and the ratio of cooling and free-fall timescales; (2) make the first high spatial resolution study of the ability of narrow (opening angle 10o) radio jets to indirectly suppress star formation in the ISM by heating the CGM and lowering the pressure and density of both on large scales. Gas from the galaxy ISM may be subsequently pushed into the CGM by supernovae; (3) better understand the ability of entropy gradients in the CGM produced by active galactic nuclei inflated “bubbles” to influence galaxy wide star formation, and how this process might depend on the galaxy’s halo mass (and the CGM’s “cosmological” entropy content).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

为了充分理解星系的演化，我们必须确定随着时间的推移塑造它们的主要过程。其中一个过程是“重子循环”，类似于地球上的水和碳循环，其中气体在星系的星际（ISM）和环星系介质（CGM）之间循环，由各种加热（例如超新星和射电喷流）和冷却机制决定，在此过程中形成复杂且动态的星系“大气”。这个过程的细节调节气体流入或流出星系，从而调节恒星的形成和星系环境的化学富集。这项研究将使用详细的数值模拟来了解银河系大气的动力学。研究人员将通过一个双用途网站支持公众教育：一个以计算机模拟的可视化为特色，第二个以交互式电子文本为特色，向学生介绍星系大气的物理学。将支持一名博士后。这项研究将通过确定其松弛的准流体静力平衡状态以及由于能量输入（例如超新星和活跃星系核）和质量吸积而偏离这些状态来研究星系大气的动力学（即组合的ISM和CGM）。三大组数值模拟将尝试：（1）更好地理解从 CGM 到 ISM 的冷气体的凝结和随后的“沉淀”如何取决于（例如）局部气体湍流、大尺度熵梯度、扰动、浮力以及冷却和自由落体时间尺度的比率； (2) 首次进行高空间分辨率研究，研究窄（张角 10o）射电射流通过加热 CGM 并在大范围内降低两者的压力和密度来间接抑制 ISM 中恒星形成的能力。来自ISM星系的气体随后可能被超新星推入CGM； (3) 更好地了解活跃星系核膨胀“气泡”产生的 CGM 中的熵梯度影响星系范围恒星形成的能力，以及这一过程如何依赖于星系的晕质量（以及 CGM 的“宇宙学”熵含量）。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查进行评估，被认为值得支持标准。