Measuring the Growth of Structure with Millimeter-Wavelength Surveys

Neelima Sehgal博士被授予美国国家科学基金会天文学和天体物理学博士后奖学金，在普林斯顿大学开展研究和教育项目。基于地面的毫米波长巡天正在进行中，通过它们的Sunyaev-Zel'dovich （SZ）信号探测到几十到几百个星系团，其中高能电子通过逆康普顿散射扭曲宇宙微波背景辐射（CMB），其中低能的CMB光子在与高能星系团电子碰撞时获得能量提升。这些调查首次测量了星系团数密度随宇宙时间的演变，并有可能提供结构增长的精确测量。反过来，这可以区分暗能量是宇宙的一个组成部分，还是广义相对论在最大尺度上失败的表现。Sehgal博士将在她之前的工作基础上，领导对阿塔卡马宇宙学望远镜探测到的sz选择的星系团样本的第一个宇宙学约束进行分析。她将在从更大更灵敏的SZ星团调查中确定宇宙学参数以及通过校准最新的多波长观测来升级毫米波长天空的模拟方面发挥主导作用。后者将有助于减少宇宙学分析中系统不确定性的来源。Sehgal博士还将探索使用毫米波模拟测量团簇特殊速度的可行性，从而评估它们作为结构生长的替代探针的实用性。Sehgal还将与新泽西天文教育中心合作，开发和支持几个系列的课程模块，向高中生传授宇宙学的关键概念。她还将培训高中教师如何使用这些模块，并通过调查评估其有效性。这些模块将分发给全国的高中。

Dr. Neelima Sehgal is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at Princeton University. Ground-based millimeter-wavelength surveys are underway and are detecting tens to hundreds of galaxy clusters by their Sunyaev-Zel'dovich (SZ) signal, in which high-energy electrons distort the cosmic microwave background radiation (CMB) through inverse Compton scattering, in which the low energy CMB photons receive energy boost during collision with the high energy cluster electrons. These surveys have presented their first measurements of the cluster number density evolution over cosmic time and can potentially provide precision measurements of structure growth. This, in turn, could discriminate between dark energy as a component of the Universe or as a manifestation of General Relativity's failure on the largest scales. Dr. Sehgal will build on her previous work to lead an analysis of the first cosmological constraints from an SZ-selected sample of galaxy clusters detected with the Atacama Cosmology Telescope. She will play a leading role in the determination of cosmological parameters from larger and more sensitive SZ cluster surveys and in upgrading simulations of the millimeter-wavelength sky by calibrating to the latest multi-wavelength observations. The latter will help reduce sources of systematic uncertainty in the cosmological analysis. Dr. Sehgal will also explore the feasibility of measuring cluster peculiar velocities using millimeter-wave simulations and thereby assess their utility as an alternative probe of structure growth.Dr. Sehgal will also work with the New Jersey Astronomy Center for Education to develop and support several series of class modules that teach high-school students about key concepts in cosmology. She will also train high-school teachers on the use of these modules and assess their effectiveness through surveys. These modules will be distributed to high-schools nationwide.