I seek to study the filamentary structure of the cosmic web, from the largest scales down to the central hubs — massive galaxy clusters. My tool of choice is gravitational lensing, in particular weak lensing. I’m a member of the CLASH team and the Dark Energy Survey collaboration.
For the first paper with data from the Dark Energy Survey, I led a large team of DES collaborators and used the Dark Energy Camera (DECam) on the CTIO 4-m telescope to study four massive galaxy clusters.
The targeted clusters were well known — one of them is the famous Bullet Cluster, the poster child of merging clusters — so that the findings from DECam data could be cross-checked with existing results. If this could be done successfully, it would not only validate the instrument and the DES analysis pipelines, but utilizing the entire 3 square degree field of view would also allow an investigation of the large-scale environment from which these clusters accrete their material.
With images and spectropscopy from SDSS, I measured, for the first time, the really weak lensing signal of cosmic voids.
The voids were identified by a sophisticated algorithm that utilizes the full three-dimensional information of positions and spectroscopic redshifts, so that we could then combine their anti-lensing effects from the tiny distortions of the shapes of backgrund galaxies. While only marginally significant (equivalent to a 2.9 σ detection), this measurement verifies that voids are as underdense in Dark Matter as they are in galaxies.