Are Hubble Residuals a Product of Poor Mass Estimates? Improving Supernova Ia Host Galaxy Characterizations

Ia型超新星(SNIa)是一种非凡的宇宙学距离指示器，曾用于发现宇宙的加速膨胀，现在正被用于精确测量暗能量的状态方程。SNIA的属性现在奇怪地显示了宿主星系属性的趋势，这使得它们作为距离的干净预测指标的使用变得复杂起来。目前，尚不清楚这些趋势是否预示着某种物理意义上的东西，或者仅仅是数据不足和测量星系属性的方法不足的表现。该项目将利用目前可用的更广泛的多波长数据集，并改进表征星系质量和其他性质的方法，重新审视这些趋势。约翰霍普金斯大学的团队将招募来自巴尔的摩地区学校的本科生实习生，重点是来自代表性和服务不足背景的学生，参与档案数据恢复、星系特征描述和最终星表的发布。这个项目的主要目标是测试哈勃残留物的存在和规模，哈勃残留物是校正后的SNIa峰值光度的过剩，似乎与宿主星系质量有关。该团队将从现有的和即将提供的红外档案中汇编一个广泛的多波长数据集，利用现有的光学数据从非参数拟合中恢复最佳的可用恒星形成历史，并从Pantheon+样本中更准确地确定SNIa宿主星系的恒星质量和恒星形成速率，这是对过去几次SNIa调查的大型汇编。利用这一完整而稳健的宿主特征目录，该团队将重新研究哈勃残留物及其对宇宙学分析的影响。此外，这个项目将允许首次估计SNIa延迟时间分布作为宿主质量的函数，并在广泛的红移范围内，从而检验哈勃残差所暗示的假设，即SNIa是多个主要前身机制的产物。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。

Type Ia supernovae (SNIa) are extraordinary cosmological distance indicators that were used in the discovery of the accelerated expansion of the universe and are now being used for precision measurements of the equation of state of dark energy. SNIa properties now curiously show trends with host galaxy properties, which complicates their use as clean predictors of distance. At present, it is not clear if these trends are indicating something physical, or if they are simply a manifestation of insufficient data and the methods that are used to measure galaxy properties. This project will revisit these trends, making use of the more extensive multi-wavelength datasets that are now available, and improved methods for characterizing galaxy masses and other properties. The team at Johns Hopkins University will enlist undergraduate interns from Baltimore-area schools, with a focus on students from underrepresented and underserved backgrounds, to participate in the archival data recovery, galaxy characterization, and publication of the final catalogs.The main goal of this program is to test the much-debated existence and magnitude of Hubble residuals, excesses in corrected SNIa peak luminosities that appear to correlate with host galaxy masses. The team will compile an extensive multi-wavelength dataset from available and soon to be available infrared archives, leveraging existing optical data to recover the best available star-formation histories from non-parametric fitting, and more accurately determine stellar masses and star-formation rates for SNIa host galaxies from the Pantheon+ sample, which is a large compilation of several past SNIa surveys. Using this complete and robust catalog of host characteristics, the team will revisit Hubble residuals and their implications for cosmological analyses. In addition, this project will allow the first estimation of SNIa delay-time distributions as a function of host mass, and over a wide redshift range, and thus test the hypothesis, implied by the Hubble residuals, that SNIa are the products of more than one dominant progenitor mechanism.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.