Mapping AGN Accretion Through Echo Mapping and Radiation MHD Simulations

从恒星和行星的形成到伽马射线暴这样最极端的爆炸，理解流向物体的物质是天体物理学中的一个普遍挑战。这个研究项目的PI使用对流入超大质量黑洞(吸积盘)的物质的观测来改进吸积模型。具体地说，我们观察到不同波长的吸积盘发出的光量随时间的变化。在很长的时间尺度上，他们可以有效地观察物质通过这种可变性向吸积盘内部移动，这反过来又告诉我们关于盘的基本情况，比如它有多厚，密度有多大。然后，他们将建立新的吸积盘模型，帮助我们准确地了解信号是如何通过吸积盘传播的。随着即将到来的维拉鲁宾太空和时间望远镜(LSST)准备观测黑洞周围数以千计的吸积盘，现在是准备好这些模型和我们的测量工具的时候了。普林斯顿的PI也将在培训下一代科学家利用LSST方面处于有利地位。除了与PI合作的学生和博士后外，他们还为以前被监禁的学生建立了一个暑期研究计划，与此项目相关的短期暑期项目将为这些学生在STEM职业生涯和未来参与LSST做好准备。活动星系核(AGN)中超大质量黑洞的吸积是宇宙中能量最高的现象之一，AGN反馈可能在星系演化中起着核心作用。然而，尽管进行了多年的研究，我们对吸积的机制仍然有一些基本的未决问题。虽然我们不能直接在空间上分辨吸积盘，但回声映射--跟踪波长的变化信号--可以告诉我们关于盘的温度分布、大小尺度，甚至长宽比。最后这一特性可以通过追踪变异性信号来探测，这些信号起源于吸积盘中很远的距离，然后在粘性时间随水流向内移动，即所谓的从红色波长移动到蓝色波长的“负”滞后。该奖项的PI在一个经过充分研究的AGN中检测到了这种负滞后，该项目的重点是通过以下方式发现更多的这种负滞后：(A)档案搜索；(B)3D辐射磁流体模拟，它将使我们深入了解响应函数，或信号向内移动时的延迟分布；(C)根据(B)项的建议，创建模拟光曲线，以优化滞后恢复和维拉鲁宾天文台遗留空间和时间调查等下一代调查的节奏。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。

Understanding material flowing onto objects is a universal challenge in astrophysics, from the formation of stars and planets to the most extreme explosions like Gamma Ray Bursts. The PIs of this research program use observations of the material flowing onto supermassive black holes (accretion disks) to refine models of accretion. Specifically, we observe changes in the amount of light from accretion disks over time at different wavelengths. Over long timescales, they can effectively watch material moving inward in the accretion disk through this variability, which in turn tells us basic things about the disk, like how thick it is, and how dense. They will then build new models of accretion disks that will help us understand exactly how the signals propagate through the accretion disk. With the upcoming Vera Rubin Telescope Legacy Survey of Space and Time (LSST) poised to observe thousands of accretion disks around black holes, now is the time to get these models and our measurement tools ready. The PIs at Princeton will also be in a strong position to train the next generation of scientists to utilize LSST. In addition to the students and postdocs that the PIs collaborate with, they have built a summer research program for formerly incarcerated students, and short summer projects associated with this project will position these students for STEM careers and future involvement in LSST. Accretion onto supermassive black holes in active galactic nuclei (AGN) is one of the most energetic phenomena in the Universe, and AGN feedback likely plays a central role in galaxy evolution. Yet, despite years of study, we still have basic open questions about the mechanisms of accretion. While we cannot directly spatially resolve accretion disks, echo mapping -- tracing variability signals with wavelength -- can tell us about the temperature profile, size scale, and even aspect ratio of the disk. This last property can be probed by tracing variability signals that originate at large distance in the accretion disk and then move inwards with the flow on a viscous time, the so-called "negative" lags that move from red to blue wavelengths. The PIs of this award have detected such a negative lag in one well-studied AGN, and this project is focused on finding more such negative lags through: (a) archival searches; (b) 3D radiation magnetohydrodynamic simulations that will give us insight into the response function, or the delay distribution of the signal as it moves inward; (c) the creation of mock light curves, informed by (b), to optimize lag recovery and the cadence of next-generation surveys like the Vera Rubin Observatory Legacy Survey of Space and Time.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.