Raising the bar for black hole mass measurements in lower mass galaxies

提高低质量星系中黑洞质量测量的标准

基本信息

批准号：
2009122
负责人：
Monica Valluri
金额：
$ 41.05万
依托单位：
Regents of the University of Michigan - Ann Arbor
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-09-01 至 2024-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2009122&HistoricalAwards=false
关键词：
Raising bar black hole mass

项目摘要

It is now known that supermassive black holes live at the centers of all galaxies. Over the past decade scientists have found that the masses of these monster black holes depend strongly on the properties of their host galaxies. Supermassive black holes, some of the most intriguing objects in the universe, also play a transformative role in how their parent galaxies evolve. While they are gigantic (between a million and a ten billion times the mass of the sun), supermassive black holes are only a fraction of a percent of the total mass of the galaxy they live in. Much is still not understood about how these black holes grew or how they were able to so dramatically influence galaxy evolution. To understand how black holes grow, it is first necessary to measure their masses, both in nearby galaxies and in distant galaxies. The ‘gold standard’ method for measuring black hole masses in nearby galaxies uses the motions of stars that orbit close to the black hole. In the nearby Universe most of the black holes that are still growing today (the so-called Active Galactic Nuclei) live in disk galaxies like our own Milky Way. The black holes in disk galaxies are less massive, and therefore are harder to study since they have weaker effects on the motion of stars around them. The team will develop training tools to allow other scientists to use their new modeling software. Several undergraduate research students will participate in this research adding to their scientific and technical training and better equipping them for future pursuits.The accurate determination of supermassive black hole masses in galaxies, both at low and high redshifts, underpins almost all efforts to understand galaxy evolution. Black hole mass measurements that use the dynamics of stars in galactic nuclei are the current ‘gold standard’. Black hole masses are found to be tightly correlated with the properties of their host galaxies over a very wide range of black hole masses (from 100 million to 10 billion times the mass of the sun). At lower black holes masses, found in predominantly disk-like galaxies, the correlations are weaker. Spiral galaxies like our Milky Way, that contain a stellar bar (a rapidly rotating cigar-like central feature) show the most scatter. The team recently found that black hole mass measurements in barred galaxies can be overestimated when the bar is ignored, especially as the galaxy is viewed more face-on. Since 65% of disk galaxies have stellar bars, this bias primarily affects black hole masses in galaxies at the low-end of the mass function. It also impacts the black hole mass scaling relations - the correlations between the host galaxy properties and black hole masses. The new black hole mass measurements resulting from this project will better constrain the statistical uncertainties on the black hole masses at the low end of the black hole mass range, where it is most uncertain. They will also aid in determining the “reverberation mapping” mass scale a relationship that is crucial for future measurements of black hole masses at high redshift. The modeling will yield detailed three-dimensional distributions of the orbits of stars in the host galactic nuclei. The open source software that will be developed during this project will have broad applicability beyond black hole mass determination. The team will also make available tutorials for using the software for modeling galaxies and involve several undergraduates in the research allowing them to apply state-of- the-art galactic dynamics modeling tools to real data.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.

现在众所周知，超级质量的黑洞生活在所有星系的中心。在过去的十年中，科学家们发现，这些怪物黑洞的质量依赖于宿主星系的特性。超大型黑洞是宇宙中一些最有趣的物体，在其父星系的发展方式中也起着变革性的作用。尽管它们是巨大的（在太阳质量的一百万到一百万倍之间），但超级质量的黑洞仅占他们所居住的星系总质量的一小部分。对于这些黑洞如何增长或它们如何如此巨大影响星系进化，仍然不了解很多东西。为了了解黑洞如何生长，首先有必要在近乎星系和遥远的星系中测量其质量。测量近星系中黑洞质量的“黄金标准”方法使用了靠近黑洞的星星的运动。在附近的宇宙中，当今仍在生长的大多数黑洞（所谓的活跃银河核）生活在我们自己的银河系中的磁盘星系中。磁盘星系中的黑洞较少，因此很难研究，因为它们对周围恒星的运动影响较弱。该团队将开发培训工具，以允许其他科学家使用其新的建模软件。几位本科生将参加这项研究，从而增加了他们的科学和技术培训，并更好地为他们提供了未来的追求。在低红移和高红移时，准确地确定了星系中超大质量的黑洞质量，几乎为了解星系进化的所有努力。使用银河核中恒星动力学的黑洞质量测量是当前的“黄金标准”。发现黑洞块与在非常广泛的黑洞质量（从太阳质量中的1亿到100亿倍）上的宿主星系的性质密切相关。在主要磁盘样星系中发现的黑色孔质量下，相关性较弱。像我们的银河系一样的螺旋星系，其中包含恒星棒（迅速旋转的雪茄般的中心特征）显示出最散射。该团队最近发现，当忽略条形杆时，可能会高估禁止星系中的黑洞质量测量值，尤其是在看到银河系的面对面时。由于65％的磁盘星系具有出色的棒，因此这种偏见会影响质量功能低端星系中的黑洞质量。它还影响黑洞质量缩放关系 - 宿主星系特性与黑洞质量之间的相关性。该项目产生的新的黑洞质量测量值将更好地限制黑洞质量范围低端的黑洞质量的统计不确定性，而黑洞质量范围最不确定。他们还将有助于确定“崇敬地图”质量尺度的关系，这对于在高红移时对黑洞的未来测量至关重要。该建模将产生宿主银河核中恒星轨道的详细三维分布。该项目期间将开发的开源软件将在黑洞质量确定之外具有广泛的适用性。该团队还将提供用于使用该软件建模星系的教程，并在研究中涉及几个大学生，使他们能够将最新的银河系动力学建模工具应用于真实数据。该奖项反映了NSF的法定任务，并通过评估该基金会的知识级别的功能和广泛的影响来审查CRETIRIA。