Collaborative Research: WoU-MMA: The Benchmark Measurement of Quasar Spectroscopic Variability and Implications for Supermassive Black Hole Binaries and Changing-Look Quasars

合作研究：WoU-MMA：类星体光谱变异性的基准测量以及对超大质量黑洞双星和变化外观类星体的影响

• 批准号: 2205719
• 负责人: Jessie Runnoe
• 金额: $ 29.7万
• 依托单位: Vanderbilt University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2205719&HistoricalAwards=false
• 关键词: Collaborative; Research; WoU; MMA; Benchmark

Most, if not all, reasonably massive galaxies host supermassive black holes in their centers, with masses of millions to billions of times the mass of the Sun. The most luminous non-exploding objects in the Universe, quasars are the result of gas falling onto these supermassive black holes and they can outshine all of the stars in their host galaxy. They are important because they appear to play a key role in shaping how galaxies came to look the way that they do today. However, because of their large cosmological distances, they appear as pinpricks of light on the sky and we cannot spatially separate the environment around the black hole to study its characteristics. Fortunately, quasars are intrinsically variable with frequent changes in brightness, making time-domain observations a powerful tool in revealing their central regions, akin to using a movie to tell a story instead of a single photograph. The research team at Vanderbilt and Penn State Universities will leverage these brightness changes and big data techniques to make the first measurement of how gas around supermassive black holes moves over a timescale of years to a decade. This will enable searches for exotic sources, like supermassive black holes in binary (SBHB) systems which have never been detected before, and changing-look quasars (CLQs) which turn on and off much faster than theory can explain. The investigators will also conduct a three-day data mining workshop for students in the Fisk-Vanderbilt Bridge Program and develop a series of introductory astronomy exercises using the popular Zooniverse interface.This project will constitute the benchmark measurement of multi-year quasar spectroscopic variability and apply it to searches for SBHBs and CLQs. This work will use a sample of approximately 5000 quasars from the Sloan Digital Sky Survey that have been observed spectroscopically more than once to measure the parameters of the broad H-beta line and their variability over times scales of 1-18 years. These will be used to define a statistical model for regular quasar variability, appropriate for many applications, including searches for SBHBs and CLQs. With this statistical tool the team will (a) compare the ensemble variability properties of SBHB candidates to a control sample for the first time, (b) test the nature of the best sub-pc separation SBHB candidates, (c) predict the necessary duration for SBHB monitoring campaigns to bear fruit, (d) constrain the masses that SBHB candidates can have, (e) determine for the first time whether CLQs represent extreme examples of normal quasar variability or a distinct phenomenon, and (f) define the CLQ class rigorously and quantitatively.This award addresses and advances the goals of the Windows on the Universe Big Idea.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.

大多数（如果不是全部的话）质量相当大的星系的中心都有超大质量黑洞，其质量是太阳质量的数百万到数十亿倍。类星体是宇宙中最明亮的非爆炸物体，是气体落在这些超大质量黑洞上的结果，它们比宿主星系中的所有恒星都要亮。它们很重要，因为它们似乎在塑造星系如何形成今天的样子方面发挥了关键作用。然而，由于它们在宇宙中的距离很大，它们在天空中看起来就像光的小点，我们无法在空间上分离黑洞周围的环境来研究它的特征。幸运的是，类星体本质上是可变的，亮度经常变化，这使得时域观测成为揭示其中心区域的有力工具，类似于用电影而不是一张照片来讲述一个故事。范德比尔特大学和宾夕法尼亚州立大学的研究小组将利用这些亮度变化和大数据技术，首次测量超大质量黑洞周围的气体在几年到十年的时间尺度上是如何移动的。这将使搜索奇异源成为可能，比如以前从未被探测到的双星系统中的超大质量黑洞，以及比理论解释要快得多的变色类星体（clq）。研究人员还将为菲斯克-范德比尔特桥项目的学生举办为期三天的数据挖掘研讨会，并使用流行的Zooniverse界面开发一系列入门天文学练习。该项目将构成多年类星体光谱变化的基准测量，并将其应用于寻找shbb和clq。这项工作将使用来自斯隆数字巡天（Sloan Digital Sky Survey）的大约5000个类星体的样本，这些类星体已经被不止一次地观测到光谱，以测量宽h - β线的参数及其在1-18年时间尺度上的变化。这些数据将用于定义一种适用于许多应用的常规类星体变异性的统计模型，包括对shbb和clq的搜索。有了这个统计工具，研究小组将(a)第一次将shbhb候选者的集合变异性属性与控制样本进行比较，(b)测试最佳次pc分离shbhb候选者的性质，(c)预测shbhb监测活动取得成果所需的持续时间，(d)限制shbhb候选者可能拥有的质量，(e)首次确定clq是正常类星体变异性的极端例子还是一种独特的现象。(f)严格和定量地定义CLQ类。该奖项旨在解决并推进“宇宙之窗大构想”的目标。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。