The Physics of Satellite Galaxy Quenching: Novel Analysis of Observations, and High-Resolution Simulations

该项目将研究导致卫星星系中恒星停止形成的物理机制。这些星系围绕更大质量的星系运行，代表了全球星系群的很大一部分。人们对它们知之甚少。拟议的研究将结合联合收割机对成像和光谱数据集的分析以及计算机模拟，以研究这些卫星星系中星星形成猝灭的物理机制。库珀博士还将教育和指导代表性不足的学生作为新的Cal-Bridge计划的一部分，该计划旨在增加从加州州立大学成功过渡到加州大学天体物理学或物理学研究生院的少数民族学生的数量。作为该计划的核心成员，库珀博士将担任一对一的导师和研究顾问，以个人卡尔桥学者，同时也开发为期一天，整个计划的专业发展研讨会，重点是从科学编码的主题，以准备GRE考试。尽管在模拟宇宙时间的大规模星系的演变成功，现代的星系形成模型无法再现低质量星系在宇宙时间内的特性。我们理论图景中的这一缺陷在很大程度上是由于无法理解卫星（或"环境"）淬火的物理学。为了解决这一缺点，拟议的研究计划采用的观测卫星星系在广泛的范围内的恒星质量和主机晕质量在z 2串联集中的半解析建模工作，以确定在发挥作用的特定物理机制，一旦一个卫星吸积到主机晕。拟议的分析将测试一个模型，饥饿和冲压压力剥离是占主导地位的淬火机制以上和以下的临界规模，分别。 库珀博士将领导一项有针对性的光谱活动，对z~1处的卫星星系进行前所未有的分类。这一努力将得到补充的统计分析卫星在z 2使用深成像在遗留的河外领域。这个项目将极大地扩展我们对物理过程的了解，这些物理过程使卫星熄灭，并推动z2静止星系群的形成，直接解决了当前星系形成模型的一个主要缺陷。此外，库珀博士将教育和指导代表性不足的学生作为新的加州桥梁计划的一部分，该奖项旨在增加从加州州立大学成功过渡到加州大学校园天体物理学或物理学研究生院的少数民族学生的数量。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响进行评估，被认为值得支持审查标准。

This project will study the physical mechanisms responsible for halting the formation of stars in satellite galaxies. These galaxies, which orbit more massive galaxies, represent a large segment of the global galaxy population. They are poorly understood. The proposed research will combine analysis of imaging and spectroscopic datasets as well as computer simulations to study the physical mechanism for quenching of star formation in these satellite galaxies. Dr. Cooper will also educate and mentor underrepresented students as part of the new Cal-Bridge program, which is designed to increase the number of minority students who successfully transition from Cal State Universities into graduate school at UC campuses in astrophysics or physics. As a core member of the program, Dr. Cooper will serve as a one-on-one mentor and research advisor to individual Cal-Bridge scholars, while also developing day-long, program-wide professional development seminars, focusing on topics ranging from scientific coding to preparation for the GRE exam.Despite success at modeling the evolution of massive galaxies over cosmic time, modern models of galaxy formation fail to reproduce the properties of low-mass galaxies over cosmic time. This shortcoming in our theoretical picture is largely driven by an inability to understand the physics of satellite (or "environmental") quenching. To address this shortcoming, the proposed research program employs observations of satellite galaxies across a broad range in stellar mass and host halo mass at z 2 in tandem with a focused semi-analytic modeling effort, to identify the particular physical mechanisms at play once a satellite is accreted onto a host halo. The proposed analysis will test a model whereby starvation and ram-pressure stripping are the dominant quenching mechanisms above and below a critical scale, respectively. Dr. Cooper will lead a targeted spectroscopic campaign to catalog an unprecedented sample of satellite galaxies in groups at z ~ 1. This effort will be complemented by a statistical analysis of satellites at z 2 using deep imaging in legacy extragalactic fields. This program will significantly expand our knowledge of the physical processes that quench satellites and drive the build-up of the quiescent galaxy population at z 2, directly addressing a major failure of current galaxy formation models. In addition, Dr. Cooper will educate and mentor underrepresented students as part of the new Cal-Bridge program, which is designed to increase the number of minority students who successfully transition from Cal State Universities into graduate school at UC campuses in astrophysics or physics.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.