Traci Johnson

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Traci Johnson

Graduate Student

University of Michigan Department of Astronomy
1085 S. University
Ann Arbor, MI 48109

Office Location(s): 406 West Hall
Phone: 734.615.6139
tljohn@umich.edu
Research Website

  • About

    BA, Carleton College/MN | Advisor: Keren Sharon

    Strong lensing in galaxy clusters

    Traci Johnson models strong gravitational lensing in galaxy clusters, the most massive structures in the universe and natural telescopes to the distant universe. The dark matter halos occupied by these clusters are massive enough to bend and deflect light from the background toward our line-of-sight, allowing us to see highly magnified, distorted, multiple images of the same background galaxies. Johnson uses the configurations of these lensed images to model the cluster mass. These models are used to derive the magnification of the source and to reconstruct the shape of the galaxy as it would be seen if not lensed. All of this information is needed to study the physical properties of the lensed galaxies, such as luminosity, morphology, substructure, and star formation rate. Strong lensing allows us to gain detailed insight into the star formation history of the universe around the time when galaxies were producing their stars most efficiently.