Eric's primary work is on doing observational cosmology with the LSST DESC.  He is currently co-leading development of the software and data analysis infrastructure for photometric redshift calibration using LSST Data.  LSST will observe about 20 billion galaxies with its six color filters. This is far more than can be observed spectroscopically, so developing, calibrating and validating methods to use the LSST color data to estimate the redshifts of these Galaxies will greatly contribute to our ability to do cosmology with the LSST Data.   Eric worked with the Fermi-LAT collaboration for years, and has many interests in gammay-ray, multi-wavelength and multi-messager astronomy.