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

2018年，科学家发现了一类具有明亮x射线和射电辐射的新型快速上升的天文事件。这些事件被称为快速和蓝色光学瞬变（FBOTs），它们比超新星（SN）或爆炸的恒星要亮得多，但在几天内变亮，比超新星通常的几十天要快得多。它们被认为是由新生的黑洞（BH）或中子星（NS）提供能量的，中子星是一种非常致密的恒星。一个由西北大学和芝加哥大学组成的研究小组将结合望远镜观测和理论研究来研究这些fbot。研究人员希望通过美国国家科学基金会资助的天文调查望远镜，如兹威基瞬变设施，每年观测到大约5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物体是如何形成的。研究人员将把他们的研究与三个教育项目结合起来：(i)为少数民族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，为他们的班级编写关于恒星爆炸的课程材料；（三）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。最近的技术进步已经彻底改变了光学天文瞬变调查（例如PanSTARRS和PTF）的调查能力，这使得探索参数空间的未知领域成为可能，并导致了新的瞬变类型的发现。的研究团队在最近的研究显示天文瞬态2018牛,相当于大FBOT——相当于达到峰值10 ~ 4 X ^ 44 erg / s,上升时间极短的几天,排除传统的SN模型由56 ni的放射性衰变,暗示小喷出物质量的0.1到0.5倍太阳质量,并指向中央引擎的存在形式的新生的NS或BH供电瞬态的显示。FBOT的射电- x射线发射提供了一个无与伦比的机会，可以在黑洞和黑洞形成时研究它们，到目前为止，这一进化阶段一直隐藏在我们的眼睛里。该研究项目独特地结合了FBOTs全色观测的优势，以及由ab-initio粒子-in - cell模拟所提供的瞬态非热特性的理论研究，其直接目标是：(1)阐明FBOTs恒星祖先的性质；（ii）对致密物体的形成过程及其诞生时的特性提供关键的见解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识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 fast-rising astronomical events with bright X-ray and radio emission was discovered in 2018. Part of the class known as Fast and Blue Optical Transients (FBOTs), these events are significantly brighter than 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 non-thermal properties of the transients informed by ab-initio 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.