Discovering Poor Groups with Strong Lenses

AST-0206084安·扎布卢什“贫穷星系群”是星系的常见环境，其中被认为驱动星系演化的机制（主要是星系-星系相互作用）比更热，更密集的星系团少。因此，任何成功的星系演化模型至少必须在大范围的红移范围内再现贫星系群的性质。 这项工作将利用引力透镜的特性作为探索星系演化的工具。 它将构成对56个已知强透镜领域中星系的第一次全面光谱观测，从那些即使是目前约束很差的透镜模型也需要来自透镜红移或附近的额外质量的贡献的星系开始。仔细的建模表明，以这种方式确定的任何群体的质量，浓度和红移都代表了动态进化群体的更大群体。这项调查将大大改善透镜分析，不仅通过表征星系的透镜环境和沿着视线，而且通过限制速度色散和质心的个别群体和速度色散的组合群体在不同的红移。因此，哈勃常数和暗能量将受到新的限制，这些限制与从更经典的方法中得出的限制是互补的。***

AST-0206084Zabludoff, Ann I."Poor groups" are common environments for galaxies in which the mechanisms thought to drive galaxy evolution (primarily galaxy-galaxy interactions) are fewer than in hotter, denser galaxy clusters. Therefore, any successful galaxy evolution model must, at the very least, reproduce the properties of galaxies in poor groups over a wide range of redshifts. This work will use the properties of gravitational lenses as a tool to explore galaxy evolution. It will constitute the first comprehensive spectroscopic observations of galaxies in the fields of the 56 known strong lenses, starting with those for which even the current, poorly-constrained lensing models require a contribution from additional mass at or near the lens redshift. Careful modeling suggests that the masses, concentrations, and redshifts of any groups identified in this manner are representative of the larger population of dynamically evolved groups. This survey will greatly improve lensing analyses not only by characterizing galaxies in the lens environment and along the line-of-sight, but also by constraining the velocity dispersion and centroid of individual groups and the velocity dispersion profiles of composite groups at different redshifts. As a result, new limits will be placed on the Hubble constant and dark energy that are complementary to those derived from more classical methods. ***