New Constraints on Feedback from a Comprehensive Study of Galactic Winds

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。自20世纪70年代以来，大质量恒星和吸积黑洞对周围星际介质的影响被称为“反馈”，被认为是星系演化的一个重要组成部分。反馈通过加热原本会形成恒星的冷云来调节恒星的形成，并通过插入动能来将气体赶出星系盘，甚至可能完全赶出潜在井。尽管在所有现代数值模拟中都包含了某种形式的反馈，但令人遗憾的是，对星系重子成分之间复杂的相互作用的理解仍然不完整。然而，一些最好的经验约束来自于对星系尺度的气体流出或“星系风”的研究。该项目将支持一名毕业论文学生进行迄今为止最雄心勃勃、最全面的星系风研究，通过对边缘盘星系样本中的平面外电离气体的直接成像，以及对近面星系的吸收线光谱来探测星系风的流出。该研究将绘制可观测值与宿主星系关键物理特性的依赖关系，如恒星质量、恒星形成速率、恒星形成表面密度、黑洞质量、活动星系核亮度和当地环境。光谱和空间信息将结合起来推断风的能量和质量流出率。这些数据将提供反馈效率的关键信息，以及星系演化数值模型的新基准。电离氢在h - α光中流出的令人印象深刻的深度图像将为公众宣传提供一个焦点，并将在公开演讲中用于展示“漂亮图片”背后的物理学。

AST-0907839TremontiThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The influence of massive stars and accreting black holes on the surrounding interstellar medium, termed 'feedback', has been regarded as an important ingredient of galaxy evolution since the 1970s. Feedback regulates star formation by heating cold clouds which would otherwise form stars, and by inserting kinetic energy which can drive gas out of the galaxy disk, and possibly completely out of the potential well. Although some form of feedback is included in all modern numerical simulations, understanding of the complex interplay between the baryonic constituents of galaxies is still woefully incomplete. However, some of the best empirical constraints come from the study of galactic-scale gaseous outflows, or 'galactic winds'. This project will support a thesis student for the most ambitious and comprehensive study of galactic winds to date, detecting outflows both by direct imaging of extra-planar ionized gas in a sample of edge-on disk galaxies, and through absorption-line spectroscopy of nearly face-on galaxies. The study will map the dependence of observables on key physical properties of the host galaxies, such as stellar mass, star formation rate, star formation surface density, black hole mass, active galactic nucleus luminosity, and local environment. Spectral and spatial information will be combined to infer the wind energetics and the mass outflow rates. These data will supply critical information on the efficiency of feedback, and new benchmarks for numerical models of galaxy evolution. The impressively deep images of outflows in the H-alpha light of ionized hydrogen will provide a focal point for public outreach, and will be used in public talks to demonstrate the physics behind a 'pretty picture'.