Ivelina Momcheva
Carnegie Observatories & Gemini South Visiting Astronomer
 

"The Environments of Strong Gravitational Lenses"
 

Strong gravitational lenses ought to be able to provide important constraints for cosmology. This promise, however, has not been met, mainly because the lack of understanding of their large-scale environments has hindered their use. I will introduce a recent spectroscopic survey of the environments and lines of sight of 28 strong galaxy-mass lenses designed to address this issue. In this talk I will present our findings on the frequency and the effect of groups associated with the lens galaxy as well as line of sight structure. I will explore the correlations between the observed lens properties and external perturbations from the observational perspective. Finally, I will discuss the effect of the environment on the value of the Hubble constant derived from observations of strong lenses.