Collaborative Research: A Multi-Wavelength Observational and Theoretical Study of the Fastest Evolving Stellar Explosions

2018 年发现了一类新的短暂天文事件。称为快速蓝色光学瞬变 (FBOT)，这些事件与超新星 (SN) 或爆炸恒星一样明亮，但在几天内变亮，比超新星通常需要数十天的时间要快得多。 据信它们由新生的黑洞（BH）或中子星（NS）提供动力，中子星是一种非常紧凑的恒星。西北大学和芝加哥大学之间的一个研究小组将结合望远镜观测和理论研究来研究这些 FBOT。 研究人员预计每年可以通过兹威基瞬态设施等国家科学基金会资助的天文巡天望远镜观测到大约五个 FBOT，使他们能够了解什么样的恒星会成为 FBOT，以及中子星和黑洞等致密天体是如何形成的。 研究人员将把他们的研究与三个教育项目结合起来：(i) 为代表性不足的少数族裔和女性本科生提供暑期研究机会； (ii) 与芝加哥地区的高中教师合作，为他们的班级开发有关恒星爆炸的课程材料； (iii) 与视障科学家和专业音乐家合作，将天文测量结果转化为声音。最近的技术进步彻底改变了光学天文瞬变巡天（例如 PanSTARRS 和 PTF）的研究能力，使人们能够探索参数空间的未知领域，并导致新型瞬变的发现。 正如研究小组在最近对天文瞬变 AT 2018cow 的研究中所显示的那样，巨大的 FBOT 光度（达到约 4 X 10^44 erg/s 的峰值光度以及极短的几天上升时间）排除了由 56Ni 放射性衰变驱动的传统 SN 模型，这意味着 0.1 至 0.5 个太阳质量的小喷射物质量，并指出了中央发动机的存在以新生 NS 或 BH 的形式为瞬态显示供电。 FBOT 发射的无线电到 X 射线为研究 BH 和 NS 形成时提供了无与伦比的机会，这是迄今为止我们看不见的进化阶段。该研究项目独特地结合了 FBOT 全色观测的优势和通过细胞内粒子模拟对其最快喷射物发射的理论研究，其直接目标是 (i) 揭示 FBOT 恒星祖细胞的性质； (ii) 对致密物体的形成过程及其诞生时的特性提供批判性的见解。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

A new class of short-lived astronomical events was discovered in 2018. Named Fast and Blue Optical Transients (FBOTs), these events are as bright as a supernova (SN), or exploding star, but brighten within a few days, much faster than the tens of days typical for supernovae. They are believed to be powered by a newly-born black hole (BH) or neutron star (NS), which is a very compact type of star. A research team between Northwestern University and the University of Chicago will study these FBOTs with a combination of telescope observations and theoretical investigations. The researchers expect to observe about five FBOTs per year from NSF-funded astronomical survey telescopes such as the Zwicky Transient Facility, enabling them to understand what kind of stars become FBOTs and how compact objects like neutron stars and black holes are formed. The investigators will integrate their research with three educational programs: (i) providing summer research opportunities to under-represented minority and women undergraduates; (ii) work with Chicago-area high school teachers to develop curricular material on stellar explosions for their classes; and (iii) work with visually impaired scientists and professional musicians to translate astronomical measurements into sound. Recent technological advances have revolutionized the investigative power of optical Astronomical Transient surveys (e.g. PanSTARRS and PTF), which allowed the exploration of uncharted territories of the parameter space, and led to the discovery of new types of transients. As the research team showed in their recent study of the Astronomical Transient AT 2018cow, the large FBOT luminosities -- reaching peak luminosities of ~4 X 10^44 erg/s -- and extremely short rise-times of a few days - rule out traditional SN models powered by the radioactive decay of 56Ni , imply small ejecta masses of 0.1 to 0.5 solar masses, and point at the presence of a central engine in the form of a newly-born NS or BH powering the transient's display. The radio-to-X-ray emission from an FBOT provides an unparalleled opportunity to study BHs and NSs at the time of their formation, a phase of evolution that has been hidden to our eyes so far. The research program uniquely combines the strengths of panchromatic observations of FBOTs and a theoretical investigation of the emission from their fastest ejecta informed by Particle-In-Cell simulations, with the immediate goals to (i) shed light on the nature of FBOTs stellar progenitors; (ii) provide critical insight onto the process of formation of compact objects and their properties at the time of birth.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.