A Spectroscopic Survey of the Fields of Strong Gravitational Lenses
AuthorWilson, Michelle Louise
galaxies: groups: general
gravitational lensing: strong
AdvisorZabludoff, Ann I.
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractThis dissertation presents an algorithm for identifying galaxy groups, describes the effects of galaxy groups in the environments of strong gravitational lenses and elsewhere along their sightlines, and investigates the properties of brightest group galaxies. We develop an algorithm to identify galaxy groups and apply it to a large spectroscopic survey in the fields of 26 strong gravitational lenses. We identify 210 groups with at least five member galaxies having velocity dispersions of 60 ≤ σ grp ≤ 1200 km s −1 over a redshift range of 0.04 ≤ z grp ≤ 0.76. Using the group catalog defined by this algorithm, we study the environments and line-of-sight structures of 26 strong gravitational lenses. Using these systems to measure cosmological parameters requires an understanding of possible systematic errors as well as the large samples to combat random uncertainties that will be discovered by future surveys. We determine the impact of ignoring lens environments and groups elsewhere along the lens sightlines on H 0 . Lens groups that would bias H 0 high by ≥ 1% exist in 23% of our fields and similarly significant line-of-sight groups in 57%. For lens systems to be used for precision cosmology, the lens environments and line-of-sight groups must be considered to avoid the systematic biases they would cause if ignored. We also study the properties of brightest group galaxies. We compare their morphological, spectroscopic, photometric, and kinematic properties to those of other group galaxies and to a sample of brightest cluster galaxies (BCGs) from Tempel et al. (2014). There is a population (38%) of elliptical, quiescent BGGs as expected from local group and cluster samples. However, our sample also includes a diversity of BGG properties, including disks, disturbed morphologies, AGN, and star formation. BGG luminosities and colors are similar to those of BCGs. However,16 BGG colors show an intermediate amount of scatter between that of BCGs and other group galaxies. BGGs and other group galaxies also have similar phase space distributions. These diverse BGG properties suggest they are still evolving.
Degree ProgramGraduate College