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

Ia型超新星（SNIa）是非凡的宇宙学距离指标，用于发现宇宙的加速膨胀，现在正用于精确测量暗能量的状态方程。SNIa特性现在奇怪地显示出宿主星系特性的趋势，这使得它们作为距离的清晰预测因子的使用变得复杂。目前，尚不清楚这些趋势是否表明了一些物理现象，或者它们只是用于测量星系属性的数据和方法不足的表现。该项目将利用现有的更广泛的多波长数据集以及描述星系质量和其他特性的改进方法，重新审视这些趋势。约翰霍普金斯大学的研究小组将招募巴尔的摩地区学校的本科实习生，重点是来自代表性不足和服务不足背景的学生，参与档案数据恢复，星系表征和最终目录的出版。该计划的主要目标是测试备受争议的哈勃残差的存在和大小，校正后的SNIa峰值亮度过高，似乎与宿主星系质量相关。该团队将从可用的和即将可用的红外档案中编译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恒星形成历史，并更准确地确定恒星质量和恒星形成速率从Pantheon+样本中SNIa宿主星系，这是过去几次SNIa调查的大型汇编。利用这个完整而强大的主机特征目录，该团队将重新审视哈勃残差及其对宇宙学分析的影响。此外，该项目将允许第一次估计SNIa延迟时间分布作为主机质量的函数，并在很宽的红移范围内，从而测试哈勃残差所暗示的假设，该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的智力价值和更广泛的评估来支持的。影响审查标准。

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.