Accretion-related feedback: star formation, black hole accretion, explosive transients

天体物理学中许多最重要的问题都是由能量反馈引起的，即来自致密引擎(如恒星、中子星或黑洞)的能量耦合到其自身的燃料供应(恒星包层、坍塌的分子云或螺旋星系)。该提案中的项目旨在整理几个关键上下文中的反馈交互。 首先，像我们这样的螺旋星系中产生的大多数恒星都是星团恒星形成的产物，在星团形成过程中，成百上千的恒星在混乱、动荡的崩塌中共同诞生。在这里，星光加热和加压气体，改变了后来几代恒星的质量；同时，风、喷流和光(最终是超新星)努力清除质量储存库，使星系团分散。然而，目前的估计认为，这些影响太弱，无法有效地清除物质；但有证据表明，它肯定是有效的。其中两个拟议的项目将改进这些估计，对星系团形成区内的辐射传输和恒星风演变进行更复杂的研究；第三个项目分析对银河系中一个巨大的星系团形成地点的观测。 其次，引力波天文学领域只有一年的历史，但探测很快就会揭示恒星质量的黑洞双星的起源。几乎可以肯定的是恒星崩塌的结果，其中一小部分是在明亮的伽马射线爆发中诞生的，人们认为这与一颗正在坍塌、快速旋转的大质量恒星有关。此外，一个黑洞可能会穿过它的伴星的包层(在一个主要的假设场景中)。在任何一种情况下，黑洞周围都会形成一个吸积盘，由于光子被捕获，因此大量的风将从该盘发出。来自这些风的能量反馈对供应圆盘的恒星产生了强烈的影响，以我打算预测和模拟的方式戏剧性地改变了结果。 第三，现代天文测量能够跟踪超新星、伽马射线爆发等时变事件，以及恒星爆发和潮汐爆发等相关现象，其中许多事件是由于恒星包层对其核心输出的能量产生反应而产生的。我和我的学生将致力于量化人们鲜为人知的爆炸类别，包括非球形超新星和不会摧毁恒星的由冲击波驱动的爆发，同时还将分析目前一项调查的数据，并为更大规模的调查做准备。

Many of the most important problems in astrophysics arise because of energetic feedback the coupling of energy from a compact engine (like a star, neutron star, or black hole) into its own fuel supply (a stellar envelope, or a collapsing molecular cloud, or a spiral galaxy). The projects within this proposal are designed to sort out feedback interactions in several key contexts. First, most of the stars created within spiral galaxies like ours are the product of clustered star formation, in which hundreds to thousands of stars are born together in a tumultuous, turbulent collapse. Here, starlight heats and pressurizes the gas, altering the masses of later stellar generations; at the same time, winds, jets, and light (and ultimately supernovae) work to clear the mass reservoir, allowing the cluster to disperse. However, current estimates set these effects too weak to clear matter effectively; but there is evidence it must be. Two of the proposed projects will improve upon these estimates with more sophisticated studies of radiation transfer and stellar wind evolution within the cluster-forming zone; a third analyzes observations of a giant cluster-forming site in the Milky Way. Second, the field of gravity wave astronomy is only a year old, but detections will soon shed much light on the origins of stellar-mass black hole binaries. Almost certainly the outcome of stellar collapse, a fraction of these are born in the brilliant gamma-ray bursts thought to involve a collapsing, rapidly rotating massive star. Moreover, one hole may plunge through the envelope of its companion star (in a leading proposed scenario). In either case, an accretion disk forms around the black hole and, since photons are trapped, a mass-loaded wind will emanate from the disk. Energetic feedback from these winds has a strong effect on the star that feeds the disk, dramatically altering the outcome in ways I intend to predict and simulate. Third, modern astronomical surveys are capable of tracking time-variable events like supernovae, gamma-ray bursts, and related phenomena like stellar outbursts and tidal disruption events, many of which result from the reaction of a star's envelope to energy output from its core. I and my students will work to quantify poorly-understood classes of explosions, including non-spherical supernovae and shock-driven outbursts that do not destroy the star, while also analyzing the data of a current survey and preparing for much larger ones.