Collaborative Research: RUI: Tracing Galaxy Quenching in the Cosmic Web With Spatially-Resolved Star-Formation Maps

甚至在认识到星系的真正性质之前，就已经认识到致密星系团中的星系看起来与这些区域外的星系(即“场”中的星系)明显不同。这种观察背后的事实是，星系的气体供应和恒星形成活动也显示出明显的对环境的依赖。这个项目的目标是更好地理解当星系穿过宇宙网到达星系团中心时，两者是如何改变的。该团队将通过测量附近14,000个星系的恒星形成和恒星盘的相对程度--比之前的研究增加了20倍--来量化恒星形成的环境“猝灭”，以理清环境、星系质量和形态的相关影响。该奖项还将让两所大学的本科生参与研究，并支持面向K-12学生的外展努力以及暑期教师培训计划。这项工作将(1)限制已知发生气体剥离的最密集环境的猝灭时间尺度，(2)确定星系团周围的宇宙细丝网络如何改变星系内恒星形成的空间分布，(3)阐明这些过程如何在不同的环境中作用，以产生观测到的变化，以及(4)产生一个具有持久遗产价值的数据集，用于研究附近宇宙的星系演化。该团队将把SERSIC模型与样本星系相匹配，并确定恒星的有效半径(来自DESI Legacy调查的光学伽玛射线带和来自WISE的红外3.4微米)和恒星形成(WISE 12微米)。通过使用紫外线(GALEX)、光学GRZ和红外(WISE)图像的椭圆口径测光，还将得到这些星系的非参数轮廓和总通量。这些互补的技术将为TO星系样本提供可靠的结构参数。将使用该团队为克服与测量大型星系的光度学相关的挑战而设计的定制软件，并将通过红外光谱能量分布分析整个样本的自洽恒星质量和恒星形成速率(SFR)。该小组将通过考虑细丝以及星系团和场成员来采用更复杂的银河系环境特征。这是一个重要的补充，因为最近的流体动力学模拟表明，细丝可能是星系转变的重要地点。这一奖项反映了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。

That galaxies in dense clusters appear markedly different from galaxies outside these regions (i.e., in the "field") was recognized even before the true nature of galaxies was recognized. Underlying this observation is the fact that a galaxy’s gas supply and star formation activity also show a marked dependence on environment. The objective of this project is to better understand how both are altered as a galaxy moves through the cosmic web to the cluster centers. The team will quantify environmental "quenching" of star formation by measuring the relative extent of the star-forming and stellar disks for 14,000 nearby galaxies - a factor of 20 increase over previous studies - to disentangle the correlated effects of environment, galaxy mass, and morphology. This award will also involve undergraduate students at both institutions in research, and support outreach efforts to area K-12 students as well as a summer teacher training program. This work will (1) constrain the quenching timescale for the densest environments where gas stripping is known to occur, (2) determine how the network of cosmic filaments around clusters alters the spatial distribution of star formation within galaxies, (3) shed light on how these processes act in different environments to produce the observed changes, and (4) produce a data set with lasting legacy value for studies of galaxy evolution in the nearby universe. The team will fit Sersic models to the sample galaxies and determine the effective radii of the stars (optical grz from the DESI Legacy Surveys and infrared 3.4um from WISE) and star formation (WISE 12um). Non-parametric profiles and total fluxes will also be derived for these galaxies through elliptical aperture photometry using ultraviolet (GALEX), optical grz, and infrared (WISE) images. These complementary techniques will yield robust structural parameters for to galaxy sample. Custom software designed by the team to overcome the challenges associated with measuring photometry of large galaxies will be used, and self-consistent stellar mass and star-formation rates (SFR) will be estimated for the entire sample through the analysis of their ultraviolet through infrared spectral energy distributions. The team will adopt a more sophisticated characterization of galaxy environment by considering filaments as well as cluster and field membership. This is an important addition as recent hydrodynamic simulations suggest that filaments may be important sites of galaxy transformation.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.