The Scaling Relations of Galaxies in the Infrared

使用新的阿塔卡马大毫米-亚毫米阵列(ALMA)设备和新一代詹姆斯·韦伯空间望远镜(JWST)进行的观测，不久将能够测量高红移星系中的恒星形成率和总可用气体质量，为研究星系在整个宇宙时间的增长提供关键信息。这两项测量是使用星系光谱的不同区域进行的。这项工作将确定这些数字是如何相关的，以及是否存在有意义的因果联系。这对于理解这些类型的研究能够实际得出观测到的星系的物理参数的可靠性是至关重要的。该项目有一个综合教育部分：(1)为来自周边地区的本科生提供暑期研究机会，让他们接触到前沿研究；以及(2)为当地中小学教师提供的研究经验，帮助他们与马萨诸塞州制定的新的“内容驱动”测试标准和国家下一代科学标准的要求保持一致。ALMA和JWST之间的协同作用将返回整个星系在高红移时的光度和物理参数范围内的恒星形成率(SFR)和气体质量(M_Gas)，从而揭示恒星形成的效率和星系作为宇宙时间的函数的增长。通常，SFR来自尘埃红外光谱能量分布(IR SED)的“蓝色”侧，而M气体则来自IR SED的“红色”侧。然而，蓝色和红色之间的二分法是人为的，IR颜色和单色发光显示出相互关联。如果存在潜在的协方差，则这些协方差可能有助于或不利于使用IR SED来推导物理参数。这个项目将确定这样的协方差，包括它们的强度，并确定它们是物理的(因果关系)还是微不足道的(例如一些共同的原因)。应用于ALMA和其他档案的贝叶斯推断方法将发现和调查协方差，以(1)调查附近星系样本中IR和远IR/毫米颜色之间的相关性；(2)确定尘埃发射的物理模型在多大程度上以及在何种假设下解释观测到的颜色-颜色相关性；(3)确定IR SED颜色-颜色相关性是否意味着光度之间的协方差。这些结果将提供应用于高红移星系的处方，特别是从IR SED中获得无偏SFRS和M_GAS的配方，以及在远距离星系中外推丢失的IR SED数据的配方，在这些星系中，完整性、深度和混乱变得重要。这一裁决反映了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。

Observations with the new Atacama Large Millimeter-submillimeter Array (ALMA) facility, and with the next generation James Webb Space Telescope (JWST), will soon enable measurement of the star formation rate and the total available mass of gas contained in galaxies at high redshifts, providing critical information for studies of the growth of galaxies across cosmic time. These two measurements are made using different regions of the galaxy's spectrum. This work will determine how the numbers are related, and whether there are meaningful causal connections. This is essential to understanding how reliably these sorts of studies can actually derive physical parameters for the observed galaxies. The project has an integrated educational component: (1) summer research opportunities for undergraduate students from the surrounding area, exposing them to cutting-edge research; and (2) research experiences for teachers from local middle and elementary schools, helping to align them with the new "content driven" testing standards set by the State of Massachusetts, and with the requirements of the national Next Generation Science Standards.The synergy between ALMA and JWST will return the star formation rate (SFR) and gas mass (M_gas) of galaxies across the full range of luminosity and physical parameters at high redshifts, thus shedding light on the efficiency of star formation and the growth of galaxies as a function of cosmic time. Commonly, the SFR is derived from the "blue" side of the infrared spectral energy distribution (IR SED) of the dust, while M_gas is derived from the "red" side of the IR SED. However, the dichotomy between "blue" and "red" sides is artificial, and IR colors and monochromatic luminosities show correlations with each other. If there are underlying covariances, then they may be either helpful or detrimental to the use of the IR SED for deriving physical parameters. This project will determine such covariances, including their strengths, and establish whether they are physical (causal correlations) or trivial (such as some common cause) in nature. Bayesian inference methods applied to the ALMA and other archives will uncover and investigate covariances, to (1) investigate the correlation between mid-IR and far-IR/mm colors in a sample of nearby galaxies; (2) establish how well, and under what assumptions, physical models of dust emission account for the observed color-color correlation; and (3) establish whether the IR SED color-color correlation implies covariance between luminosities. The results will provide prescriptions for application to high redshift galaxies, specifically, recipes for deriving unbiased SFRs and M_gas from the IR SED and for extrapolating missing IR SED data in distant galaxies where issues of completeness, depth, and confusion become important.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.