LEAPS-MPS: Constraining Supernova Explosion Models by Alpha Elements in Metal Poor Galaxies and the Intracluster Medium

一旦宇宙冷却到足以形成中性原子(大爆炸后约378,000年)，它最初的化学成分仅限于氢、氦和锂。从行星到生命，元素周期表中的其他元素都是在随后的140亿年里在恒星中锻造出来的，无论是在它们的一生中，还是在它们作为超新星(SNE)的灾难性自毁过程中，后者分散了新形成的元素。这些产物可以通过近地天体残骸和恒星的光谱以及充填在恒星(星际介质；ISM)和星系团星系(星系团内介质；ICM)之间的气体的光谱直接观察到，并限制了宇宙中的富集史。最近对贫金属星系以及英仙座星系团ICM的观测发现，在核坍塌(II型)SNE中合成的阿尔法元素(即O、Ne、Si、S、Ar和Ca)的丰度与模型预测之间存在系统失配。首席研究员(PI)将带领一组本科生研究人员确定造成这种不匹配的物理过程，并开发一系列新的SNE模型，以更好地解释观测到的丰度模式。该项目将招募代表人数不足的学生参加研究实习(每年6次)和一个暑期项目，并使PI能够进行公共科学讲座。PI和他的团队将开发一个SNE模型“流水线”，其中包括(1)用于计算直到核心塌缩开始的一系列大质量恒星模型的高级恒星演化代码，(2)用于模拟爆炸阶段的一维和多维流体动力学代码，以及(3)后处理核合成。该团队将探索混合、爆炸能量和反应速率等模型参数对阿尔法元素生产的影响，并使用观测数据对这些参数施加限制。他们将选择能够很好地再现化学丰度的参数集，并将其作为基础来生成具有各种参数的化学产额的恒星模型目录，如前体质量和金属丰度。他们还将维护一个数值SNE库，以帮助天文学家确定由未来天文台确定的SNE的起源。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。

Once the universe cooled sufficiently for neutral atoms to form (~378,000 years after the Big Bang), its initial chemical composition was limited to hydrogen, helium, and lithium. The other elements in the periodic table necessary for everything from planets to life were all forged over the subsequent 14-billion years in stars, both during their lifetimes and in their cataclysmic self- destruction as supernovae (SNe), with the latter dispersing the newly formed elements. These products can be observed directly via spectroscopy of SNe remnants and stars, as well as the gas filling the space between stars (interstellar medium; ISM) and cluster galaxies (intracluster medium; ICM), and constrain the history of enrichment in the universe. Recent observations of metal poor galaxies, as well as the Perseus cluster ICM, find systematic mismatches between the abundances of alpha elements synthesized in core-collapse (Type II) SNe (i.e., O, Ne, Si, S, Ar, and Ca) and model predictions. The principal investigator (PI) will lead a team of undergraduate researchers to identify the physical processes responsible for this mismatch and develop a new series of SNe models to better account for the observed abundance patterns. The project will recruit underrepresented students for participation in research internships (six per year) and a summer program, as well as enabling public science talks by the PI.The PI and his team will develop a SNe model "pipeline" that includes (1) an advanced stellar evolution code for computing a sequence of massive star models up to the onset of core-collapse, (2) 1-D and multi-dimensional hydrodynamics codes for modeling the explosion phase, and (3) post-processing nucleosynthesis. The team will explore the effects of model parameters such as mixing, explosion energy, and reaction rates, on the production of alpha-elements and use observational data to place constraints on these parameters. They will select the parameter set where the chemical abundances can be well reproduced and use it as a basis to generate a catalogue of stellar models with chemical yields of various parameters, such as the progenitor mass and metallicity. They will also maintain a library of numerical SNe to help astronomers identify the origin of SNe identified by future observatories.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.