How Do Galaxies End Their Star-Formation?

该项目将调查从恒星形成过渡到非恒星形成的星系群，其准确性比以前更高。该奖项支持的主要研究员和研究生将结合联合收割机斯隆数字巡天的光波长数据，银河演化探测器（GALEX）航天器的紫外线数据，以及宽视场红外巡天探测器（WISE）航天器的中红外线数据，以识别过渡星系并限制其金属丰度，恒星形成率，尘埃分布，恒星质量，和低红移处的活性核含量。然后，他们将使用PRIMUS，一个120，000星系调查，在0.2和1.0之间的红移范围内取样，结合GALEX和斯皮策太空望远镜数据，在更高的红移下进行类似的分析。其目标是：（1）获得一个准确的和有代表性的人口普查的过渡人口;（2）以确定是否恒星形成关闭孤立星系在集群人口相同的方式;（3）以确定是否活动星系核与过渡现象。除了支持研究生培训外，该项目还将扩大美国航天局-斯隆星系图集，以纳入新发布的WISE数据，并在现有网络界面内开发教育和推广工具。

This project will investigate the population of galaxies that are in transition from star-forming to non-star-forming, with greater accuracy than was previously possible. The Principal Investigator and graduate students supported by the award will combine optical-wavelength data from the Sloan Digital Sky Survey, ultraviolet data from the Galaxy Evolution Explorer (GALEX) spacecraft, and mid-infrared data from the Wide-Field Infrared Survey Explorer (WISE) spacecraft, to identify transition galaxies and to constrain their metallicities, star-formation rates, dust extinctions, stellar masses, and active nucleus content at low redshift. They will then use PRIMUS, a 120,000 galaxy survey sampling the redshift range between 0.2 and 1.0, combined with GALEX and Spitzer Space Telescope data, to perform a similar analysis at higher redshift. The objectives are (1) to obtain an accurate and representative census of the transition population; (2) to determine whether star-formation is turning off the same way in isolated galaxies as in cluster populations; and (3) to determine whether active galactic nuclei are related to the transition phenomenon. In addition to supporting graduate student training, the project will enable expansion of the NASA-Sloan Atlas of galaxies to include newly released WISE data and development of educational and outreach tools within the existing web interface.