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寿命天文事件。这些事件被命名为快速和蓝色光学瞬变(FBOT)，亮度与超新星(SN)或正在爆炸的恒星一样亮，但在几天内变亮，比超新星典型的几十天快得多。它们被认为是由新生的黑洞(BH)或中子星(NS)提供动力的，中子星是一种非常紧凑的恒星类型。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。研究人员希望每年从NSF资助的天文观测望远镜(如兹维基瞬变设施)观测到大约5个FBOT，使他们能够了解什么样的恒星成为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)为未被充分代表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，为他们的课程开发关于恒星爆炸的课程材料；以及(Iii)与视障科学家和专业音乐家合作，将天文测量转化为声音。最近的技术进步使光学天文瞬变测量(如PanSTARRS和PTF)的研究能力发生了革命性的变化，这使得能够探索参数空间的未知领域，并导致了新类型的瞬变的发现。正如研究小组在最近对2018CoW的天文瞬变的研究中所显示的那样，FBOT的大亮度--达到~4×10^44erg/S的峰值亮度--以及极短的几天上升时间--排除了由56Ni的放射性衰变提供动力的传统SN模型，意味着小质量的喷出物质量为0.1到0.5个太阳质量，并表明存在一个中央引擎，其形式为新生的NS或BH，为瞬变的显示提供动力。来自FBOT的射电到X射线的发射为研究BHS和NSS形成时的BHS和NSS提供了一个无与伦比的机会，到目前为止，这一进化阶段一直被我们的眼睛所隐藏。该研究计划独一无二地结合了对FBOTS的全色观测的优势和对其最快喷出物通过粒子在细胞中的模拟而产生的排放的理论研究，近期目标是(I)阐明FBOTS恒星前体的性质；(Ii)对致密天体的形成过程及其诞生时的性质提供关键的洞察。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.