Core Collapse Supernova Gravitational Wave Signature Predictions Based on 3D Ab Initio Models with Increasing GR Realism

核心塌陷超新星(CCSN)是标志着大质量恒星死亡的灾难性事件，这些猛烈的爆炸是元素周期表中大多数元素的原因。牛顿发展的引力理论不足以描述CCSN机制中的极端密度。因此，CCSN代表了爱因斯坦引力理论的一个极好的试验台。这个项目将推进目前CCSN模型中对引力的描述，从本质上是牛顿的描述，经过简单的修正，考虑到一些爱因斯坦效应，变成更复杂的爱因斯坦引力的近似，从而显著提高未来CCSN研究的现实性。新的模型将被用来预测核心坍塌超新星中的引力波的发射，时空结构中的涟漪。这类超新星是产生激光干涉引力波天文台(LIGO)可探测到的引力波的三个主要来源之一。PI将与LIGO协作成员密切合作，开发用于LIGO数据分析的新工具。这个项目将培训一名CCSN理论和引力波天文学的研究生，并将为Fisk-Vanderbilt博士计划的实习生提供研究机会。核心塌缩超新星的高级多物理模型，包括具有一整套中微子弱相互作用的多频率中微子传输和关键的相对论修正，如引力红移，到目前为止只实现了一个有效的自引力势，它是使用通过求解泊松方程并对单极项进行修正而获得的牛顿势来计算的。后者是由使用角平均密度的托尔曼-奥本海默-沃尔科夫方程的积分公式确定的。更现实的CCSN模型需要对一般相对论引力进行更复杂的处理。在这个项目中，Pi和他的学生将在CCSN模型中实现共形平坦近似。这一近似已被证明能很好地描述没有快速自转或黑洞形成的系统中的广义相对论引力，适用于大多数CCSN研究。新模型将用于计算CCSN模型中使用弱场慢运动近似的引力辐射发射，并将向引力波天文学社区提供新的引力波数据。

Core Collapse Supernovae (CCSN) are catastrophic events that mark the death of massive stars and these violent explosions are responsible for most of the elements in the Periodic Table. The theory of gravity developed by Newton is not sufficient to describe the extreme densities in the CCSN mechanism. As such, CCSN represent an excellent test bed for Einstein's theory of gravity. This project will advance the description of gravity in current CCSN models, from an essentially Newtonian description with a simple correction accounting for some Einsteinian effects to a far more sophisticated approximation of Einsteinian gravity, thereby improving significantly the realism of future CCSN studies. The new models will be used to make predictions for the emission of gravitational waves, ripples in the fabric of space-time, in core collapse supernovae. Such supernovae are among the three primary sources that will produce gravitational waves detectable by the Laser Interferometric Gravitational Wave Observatory (LIGO). The PI will work closely with members of the LIGO Collaboration to develop new tools for LIGO data analysis. This project will train a graduate student in CCSN theory and gravitational wave astronomy and will provide a research opportunity for an intern in the Fisk-Vanderbilt Ph.D. program.Advanced multi-physics models of core collapse supernovae that include multi-frequency neutrino transport with a complete set of neutrino weak interactions and key relativistic corrections such as gravitational redshift, have implemented to date only an effective self-gravitational potential, which is computed using the Newtonian potential obtained by solving the Poisson equation with a correction to the monopole term. The latter is determined from an integral formulation of the Tolman-Oppenheimer-Volkoff equation using angle-average densities. More realistic CCSN models require more sophisticated treatments of the general relativistic gravity. In this project, the PI and his students will implement the Conformally Flat Approximation in CCSN models. This approximation has been shown to describe well general relativistic gravity in systems without rapid rotation or black hole formation, suitable for most CCSN studies. The new models will be used to compute the emission of gravitational radiation in CCSN models using the weak-field, slow-motion approximation and will provide new gravitational wave data to the gravitational wave astronomy community.