Astrophysical transients and compact objects

天体物理瞬变和致密天体

• 批准号: RGPIN-2017-04286
• 负责人: Fernandez, Rodrigo
• 金额: $ 1.89万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=710462
• 关键词: Astrophysical; transients; compact; objects

This research program aims to understand the physics of cosmic explosions related to stellar-mass compact objects. The initial focus is on neutron star mergers and core-collapse supernovae. These explosions operate under extreme conditions not achievable in laboratories on Earth, and thereby connect to frontier questions in physics such as the properties of matter at supra-nuclear densities, the origin of heavy elements, the nature of gravity, and the properties of neutrinos. The long-term goal of the program is to improve our theoretical understanding of this class of cosmic explosions through scientific computing, thereby contributing to more reliable observational predictions and to test physical theories. Numerical methods are required given the complexity of the processes involved. Highly-qualified personnel trained in high-performance computing and advanced analysis techniques will be one of the many beneficial results of this program. Neutron star mergers are likely to be detected in gravitational waves in the period 2017-2021 by Advanced LIGO/Virgo. Concurrent detection of electromagnetic emission will significantly decrease uncertainties in the gravitational wave signal and provide a wealth of additional information. The first short-term goal of the program is to improve predictions for the most easily detectable electromagnetic signal generated by these events: a supernova-like transient powered by the radioactive decay of r-process elements (a so-called kilonova). To this end, multi-dimensional, multi-physics, time-dependent simulations of the merger remnant will be conducted. These simulations will systematically address current uncertainties in modeling, thus improving observational and nucleosynthetic predictions for the global observational community. The explosion mechanism of core-collapse supernovae remains an unsolved theoretical problem, despite a firm observational association between these supernovae and the death of massive stars. These explosions enrich the Universe with heavy elements, and are the birth sites of neutron stars and stellar-mass black holes. Existing evidence suggests that the explosion mechanism is intrinsically asymmetric. The second short-term goal of the program is to investigate the effect of hydrodynamic instabilities that break spherical symmetry: the Standing Accretion Shock Instability (SASI) and neutrino-driven convection. Multi-dimensional simulations at different levels of sophistication will be carried out to clarify the physics of these instabilities in new regimes and the resulting observational consequences. The results will have implications for the expected neutrino- and gravitational wave signal from the next Galactic core-collapse supernova, and will shed light on related astrophysical issues such as the distribution of pulsar spins and kicks at birth.

该研究计划旨在了解与恒星质量致密物体有关的宇宙爆炸物理学。最初的重点是中子星星合并和核心坍缩超新星。这些爆炸在地球实验室无法实现的极端条件下进行，因此与物理学中的前沿问题有关，例如超核密度下物质的性质，重元素的起源，引力的性质和中微子的性质。该计划的长期目标是通过科学计算提高我们对这类宇宙爆炸的理论理解，从而有助于更可靠的观测预测和测试物理理论。考虑到所涉及的过程的复杂性，需要数值方法。在高性能计算和先进分析技术方面训练有素的高素质人员将是该计划的许多有益成果之一。 中子星星合并可能会在2017-2021年期间被Advanced LIGO/Virgo在引力波中探测到。同时探测电磁辐射将大大减少引力波信号的不确定性，并提供丰富的额外信息。该计划的第一个短期目标是改善对这些事件产生的最容易检测的电磁信号的预测：由r过程元素的放射性衰变（所谓的kilonova）提供动力的超新星般的瞬变。为此，将对合并残余物进行多维、多物理场、随时间变化的模拟。这些模拟将系统地解决目前建模中的不确定性，从而改善全球观测界的观测和核合成预测。 核心坍缩超新星的爆炸机制仍然是一个未解决的理论问题，尽管这些超新星和大质量恒星的死亡之间有着坚定的观测联系。这些爆炸使宇宙充满了重元素，是中子星和恒星质量黑洞的诞生地。现有的证据表明，爆炸机制本质上是不对称的。该计划的第二个短期目标是研究打破球对称的流体动力学不稳定性的影响：静止吸积激波不稳定性（SASI）和中微子驱动的对流。将进行不同复杂程度的多维模拟，以澄清新制度中这些不稳定性的物理性质以及由此产生的观测后果。这些结果将对下一个银河系核心坍缩超新星的预期中微子和引力波信号产生影响，并将揭示相关的天体物理问题，如脉冲星旋转和出生时的分布。