Probing Accretion and Relativistic Jet Physics with the Dynamic Multimessenger Universe

大多数物质聚集到天体上的物理过程，即吸积，与第二种物理过程，即流出密切相关。天体物理学家将高度聚焦的流出物称为“喷流”。在我们的宇宙中，大多数观测到的喷流都涉及到将单个电子和大量粒子的数量加速到相对论速度（即接近光速的速度）的过程。吸积和相对论性喷流会产生明亮的电磁信号。吸积通常在X射线波长处是明亮的。相对论性喷流在近红外波段通过无线电波长是明亮的。经历吸积和天体物理喷流爆发的源，为我们银河系的极端细节研究和整个可观测宇宙的大规模、不太详细的研究提供了信标。尽管我们知道这些来源已经有50多年了，但我们仍然无法回答：“是什么过程加速了喷气机？”不同类型的喷气机发射方式有何不同？以及这些源在星系形成中的确切作用是什么？”我的长期目标是回答这些关键问题，这些问题适用于从诞生的单个恒星到位于星系中心的质量是太阳数十亿倍的黑洞的物体。考虑到源类型的广泛范围，理解吸积和喷流之间的联系是天体物理学的一个高度优先的目标。天体物理学家最近将天体物理喷流与我们可以用非电磁信号（例如，来自高速粒子的信号，如中微子和引力波）研究的第一个河外事件联系起来。为了探索吸积和喷流之间的物理联系，更好地理解多信使源，天体物理学家必须测量喷流的特性，并在可能的情况下，将这些特性与吸积的特性联系起来。我的短期研究计划将利用电磁频谱的时域观测的多种途径来提供这些数据和理论解释。我将结合：1)利用一系列国际设施（包括加拿大国家研究委员会或加拿大航天局共同支持的设施），在积极吸积的恒星质量黑洞和中子星的电磁频谱上进行几乎同时的定时和成像观测；2)揭示大量天体物理物体的射电和X射线特性的调查，这将使我的团队能够确定这些物体的性质，约束整个种群的特性，并激励对最极端物体的详细跟踪；3)领导加拿大多信使天体物理学团体对中微子和引力波事件的无线电响应。培养博士后1人，博士3人，硕士4人，本科生5人。我还将接待5名南非研究生赴加拿大进行为期3个月的科学培训。

The physical processes by which most matter accumulates onto astrophysical objects, accretion, are intimately tied to a second set of physical processes, outflows. Astrophysicists call the most highly focused outflows "jets." Most observed jets in our Universe involve processes that accelerate populations of both individual electrons and the bulk outflow of particles to relativistic speeds (i.e., speeds near that of light). Accretion and relativistic jets lead to bright electromagnetic signals. Accretion is often bright at X--ray wavelengths. And relativistic jets are bright at near--infrared through radio wavelengths. Sources undergoing outbursts of accretion and astrophysical jets serve as beacons for both extreme-detail studies in our Galaxy and en masse, lesser-detail studies across the observable Universe. Despite knowing of such sources for more than 50 years, we still cannot answer: "What process or processes accelerate jets?; What differentiates how different types of jets are launched?; and What is the precise role of these sources in galaxy formation?". My long-term goal is to answer these critical questions that apply to objects ranging from individual stars as they are being born to black holes billions of times as massive as the Sun sitting at the centre of galaxies. Given the broad gamut of source types, understanding the connection between accretion and jets is a high--priority goal in astrophysics. Astrophysicists have recently linked astrophysical jets with the first extragalactic events that we can study with non-electromagnetic signals (e.g., signals from high-speed particles, like neutrinos, and gravitational waves). To probe the physics connecting accretion and jets and better understand multi-messenger sources, astrophysicists must measure the properties of jets and, where possible, tie these to properties of accretion. My short-term research program will exploit multiple avenues of time--domain observations across the electromagnetic spectrum to provide these data and theoretical interpretations. I will combine: 1) nearly--simultaneous timing and imaging observations across the electromagnetic spectrum of actively accreting stellar-mass black holes and neutron stars using sets of international facilities (including National Research Council of Canada or Canadian Space Agency co-supported facilities); 2) surveys that reveal the radio and X--ray properties of large numbers of astrophysical objects that will enable my group to identify the nature of these objects, constrain the properties of entire populations, and motivate detailed followup of the most extreme objects; and 3) lead the Canadian multi--messenger astrophysics community's radio response to neutrino and gravitational wave events. I will train 1 Postdoctoral Fellow, 3 Ph.D. students, 4 M.Sc students, and 5 undergraduate students. I will also host 5 South African graduate students for three-month visits to Canada for scientific training.