Probing Accretion and Relativistic Jet Physics with the Dynamic Multimessenger Universe

大多数物质在天体上积累的物理过程，即吸积，与第二组物理过程，即外流密切相关。天体物理学家把最集中的外流称为“喷流”。“在我们的宇宙中观察到的大多数喷流都涉及到将单个电子和大量粒子外流加速到相对论速度的过程（即，速度接近光速）。吸积和相对论喷流导致明亮的电磁信号。吸积物在X射线波长处通常是明亮的。相对论性喷流在近红外线到无线电波段都很明亮。经历吸积和天体物理喷流爆发的源可以作为我们银河系中极详细研究的信标，也可以作为整个可观测宇宙中不太详细的研究的信标。尽管50多年来人们一直知道这些来源，但我们仍然不能回答：“是什么过程加速了喷流？不同类型喷气发动机的发射方式有什么区别？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，这些问题适用于从单个恒星诞生到黑洞的物体，黑洞的质量是太阳的数十亿倍，位于星系中心。鉴于源类型的广泛性，了解吸积和喷流之间的联系是天体物理学的一个高度优先目标。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研究的第一个河外事件联系起来（例如，来自高速粒子的信号，如中微子和引力波）。为了探索连接吸积和喷流的物理学，并更好地理解多信使源，天体物理学家必须测量喷流的属性，并在可能的情况下将其与吸积的属性联系起来。我的短期研究计划将利用多种途径的时域观测整个电磁频谱，以提供这些数据和理论解释。我将联合收割机：1）使用多套国际设施，在活跃吸积的恒星质量黑洞和中子星的电磁频谱上几乎同时进行定时和成像观测（包括加拿大国家研究理事会或加拿大航天局共同支助的设施）; 2）调查显示无线电和X--大量天体的射线特性，这将使我的团队能够识别这些天体的性质，约束整个种群的特性，和激励最极端的对象的详细跟踪;和3）领导加拿大多信使天体物理学社区的无线电响应中微子和引力波事件。培养博士后1名，博士3名。学生，4名理科硕士学生和5名本科生。我还将接待5名南非研究生到加拿大进行为期三个月的科学培训。

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.