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于能量反馈而产生的，能量反馈是来自一个紧凑的引擎（如星星、中子星星星或黑洞）的能量耦合到它自己的燃料供应（恒星包层、坍缩的分子云或螺旋星系）中。 本提案中的项目旨在整理几个关键背景下的反馈互动。 首先，像我们这样的螺旋星系中产生的大多数恒星都是集群星星形成的产物，其中数百到数千颗恒星在动荡不安的崩溃中诞生。 在这里，星光加热并加压气体，改变后来恒星世代的质量;同时，风，喷流和光（最终是超新星）工作以清除质量库，使星团分散。 然而，目前的估计将这些影响设定得太弱，无法有效地清除物质;但有证据表明它必须如此。 其中两个项目将通过对星团形成区内的辐射传输和恒星风演化进行更复杂的研究来改进这些估计;第三个项目分析了银河系中一个巨大星团形成地点的观测结果。 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黑洞双星的起源。 几乎可以肯定是恒星坍缩的结果，其中一小部分是在明亮的伽马射线爆发中产生的，这种爆发被认为与坍缩、快速旋转的大质量星星有关。 此外，一个黑洞可能会穿过它的伴星星星的外壳（在一个领先的设想方案中）。 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，一个质量负载的风将从吸积盘中发出。 来自这些风的能量反馈对供给圆盘的星星有很强的影响，以我打算预测和模拟的方式戏剧性地改变了结果。 第三，现代天文观测能够追踪随时间变化的事件，如超新星、伽马射线爆发，以及恒星爆发和潮汐破裂等相关现象，其中许多是由星星的外壳对核心能量输出的反应造成的。 我和我的学生们将致力于量化人们对爆炸理解不深的类别，包括非球形超新星和不会摧毁星星的冲击波驱动的爆发，同时还将分析当前调查的数据，并为更大的爆炸做准备。

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.