Collaborative Research: Connecting Models to Observations of Tidal Disruption Events

超大质量黑洞(SMBH)对恒星的分裂和随后的吸积与在附近星系核中观察到的许多发光耀斑有关。然而，我们对这些潮汐破坏事件(TDEs)的理论理解仍然不完整。加州大学圣克鲁斯分校、加州大学伯克利分校和西北大学之间的一项研究合作将汇集不同物理领域的专家：流体动力学、一般相对论和辐射传递，以解决我们对TDEs理解中的重要差距。这种理解需要多管齐下的方法，试图在广泛的物理和时间尺度上解决潜在的物理问题。TDEs现象提供了一个令人兴奋的机会来研究静止星系中SMBH的大小，星系核中的恒星数量和动力学，以及在明确定义的条件下黑洞吸积的物理。虽然活跃的星系核可能数千年来一直由源源不断的燃料供应，但当质量吸积率和进食时间在几天或几个月内发生变化时，TDEs提供了一个研究单个SMBH的独特机会。该项目还将包括一个教育和公共推广计划，旨在交叉培养计算科学家和学生在视觉艺术和数字媒体方面的培训，使用最先进的模拟作为集体环境中的共同点，显著增加接受计算天体物理学培训的人数不足的学生的数量。为了做到这一点，天文学家将与大学艺术和教育项目以及当地学校合作。广域瞬变调查目前正在提供更多和更好的关于TDEs的数据。对吸积盘进行全三维模拟的计算代价很高，因此需要在运行高分辨率的模拟和中等分辨率的全局模拟之间进行权衡，前者仅能分辨磁盘的一小部分，后者能分辨整个结构。对于TDES来说，取舍更加明显，需要同时解决大范围的问题。因此，对包含上述所有影响的完整问题进行单一模拟不仅是令人望而却步的，而且由于不同规模的各种物理机制之间相互作用的复杂性，也很难解释。作为另一种选择，研究人员将致力于通过一系列数值实验来回答这些问题，这些实验分离出控制破裂本身的关键过程、碎片盘的形成、喷流的产生和辐射的产生。除了在计算上可行之外，这种方法还将使人们能够透彻地了解每一个过程，这很可能使人高度想起稳定增长的活动星系核的充分研究的现象学。这一奖项反映了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。

The disruption and subsequent accretion of stars by super-massive black holes (SMBHs) has been linked to many luminous flares observed in the nuclei of nearby galaxies. Our theoretical understanding of these tidal disruption events (TDEs), however, remains incomplete. A research collaboration between the University of California Santa Cruz, the University of California Berkeley, and Northwestern University will bring together experts in different fields of physics: hydrodynamics, general relatively and radiative transfer to address important gaps in our understanding of TDEs. This understanding requires a multi-pronged approach that attempts to resolve the underlying physics at a wide range of physical and temporal scales. The phenomena of TDEs provide an exciting opportunity to study the size of SMBHs in quiescent galaxies, the stellar populations and dynamics in galactic nuclei, and the physics of black hole accretion under well-defined conditions. Whereas active galactic nuclei may be supplied by a steady stream of fuel for thousands of years, TDEs offer a unique opportunity to study a single SMBH when the mass accretion rates and feeding timescales change over days or months. The project will also include an education and public outreach program which aims to cross-fertilize the training of computational scientists and students in the visual arts and digital media using state-of-art simulations as common ground in a group environment that significantly increases the number of under-represented students trained in computational astrophysics. To do this, the astronomers will partner with university arts and education programs and with local schools. Wide-field transient surveys are currently delivering more and better data on TDEs. Fully three-dimensional simulations of accretion disks are computationally expensive, and as a result there is trade-off between running a simulation with significant resolution that only resolves a fraction of the disk and global simulations at moderate resolution that resolve the full structure. For TDEs the trade-offs are even more pronounced and require a large range of scales to be resolved simultaneously. As a consequence, running a single simulation of the full problem incorporating all of the aforementioned effects would not only be prohibitive, but also difficult to interpret because of the complexity of the interplay between the various physical mechanisms at different scales. As an alternative, the investigators will aim to answer these questions via a series of numerical experiments that isolate the key processes that regulate the disruption itself, the formation of the debris disk, the production of jets and the generation of the emanating radiation. In addition to being computationally feasible, this approach will enable a thorough understanding of each of the processes, which are likely highly reminiscent of the well-studied phenomenology of steadily-accreting AGN.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.