Probing Accretion and Relativistic Jet Physics with the Dynamic Multimessenger Universe

用动态多信使宇宙探测吸积和相对论喷流物理

• 批准号: RGPIN-2021-04001
• 负责人: Sivakoff, Gregory
• 金额: $ 3.64万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=742811
• 关键词: Probing; Accretion; Relativistic; Jet; Physics

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.

大多数物质积聚在天体物理对象上的物理过程，积聚，与第二组物理过程，流出密切相关。天体物理学家称最高的流出流程为“喷气机”。在我们宇宙中，大多数观察到的喷气机涉及加速单个电子和颗粒的批量流出的过程，即相对论速度（即，速度接近光的速度）。积聚和相对论喷气机导致明亮的电磁信号。 X-射线波长的积聚通常是明亮的。相对论的喷气机在接近射线波长的近乎近距离。经历了积聚和天体物理喷气机的爆发的消息来源，是我们银河系中极端研究的信标，在整个可观察到的宇宙中，较小的详细研究。尽管知道这种来源已有50多年了，但我们仍然无法回答：“哪些过程或过程加速了喷气机？；哪些不同类型的喷气机的启动是什么区别？；这些来源在银河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，这些关键问题适用于单个恒星的物体，因为它们出生于黑洞数十亿次，就像坐在星系中心的太阳一样大。鉴于源类型的广泛范围，了解积聚与喷气机之间的联系是天体物理学中的一个高优势目标。天体物理学家最近将天体物理喷头与我们可以使用非电磁信号（例如，来自中微子等高速颗粒的信号和引力波的信号）进行研究的第一个事件联系起来。为了探测连接积聚和喷气机的物理学，并更好地了解多通信源，天体物理学家必须测量喷气机的特性，并在可能的情况下将它们与吸积的特性联系起来。我的短期研究计划将利用多个时间途径 - 跨电磁频谱的域观测值，以提供这些数据和理论解释。我将结合：1）使用国际设施集（包括加拿大国家研究委员会或加拿大空间局共同支持的设施），在电磁频谱上进行了几乎相似的时间和成像观察结果； 2）揭示大量天体物理对象的无线电和X射线特性的调查，这些物体将使我的小组能够识别这些对象的性质，限制整个人群的特性，并激发最极端对象的详细随访； 3）领导加拿大多门纪生天体物理学社区对中微子和重力波事件的无线电反应。我将培训1个博士学位的博士后研究员。学生，4个M.SC学生和5名本科生。我还将接待5名南非研究生进行三个月访问加拿大的科学培训。