Research Interests Lyman Alpha galaxies Rhoads has been a pioneer in the study of high redshift Lyman alpha galaxies. These are galaxies selected by strong emission in the Lyman alpha line, which is the n=2 to 1 transition of atomic hydrogen. Such strong Lyman alpha emission was suggested as a signpost of young galaxies in formation by Partridge and Peebles in 1967. Thirty years later, James Rhoads, Sangeeta Malhotra, and collaborators were among the first to successfully identify field galaxies in the distant universe using this line emission. Lyman alpha galaxies are now recognized as one of the major classes of high redshift galaxies, and are prime targets for present and future study with HST, JWST, and WFIRST. Green Pea galaxies Green Pea galaxies are nearby galaxies with extremely strong emission lines in their optical spectra. They were named by citizen scientist volunteers in the Galaxy Zoo project, because they appear small, round, and green in color-composite Sloan Digital Sky Survey images. Their unusual color is because the optical emission lines are strong enough to dominate over starlight in their colors. Rhoads's collaborators have shown that green peas are good nearby analogs of high redshift Lyman alpha galaxies. Their relative proximity allows detailed study of many properties that simply cannot be studied well at the distances of high-redshift Lyman alpha galaxies. These include detailed studies of Lyman alpha line profiles, chemical abundances, and gas content. Gamma Ray Burst Afterglows Rhoads began studying on gamma ray burst afterglows four years before they were discovered. Working with Bohdan Paczynski, he heleped develop a model for radio afterglows of gamma ray bursts. This model was an early version of the modern fireball model for GRB afterglows, differing in only a few details. The first observations of GRB afterglows in 1997 enabled the distances to GRBs to be finally measured, and eliminted an uncertainty of ten orders of magnitude in the GRB energy scale. Rhoads then turned to the largest remaining uncertainty, that associated with the unknown collimation of GRB emission. He developed two tests for collimation, one based on the statistics of "orphan afterglows", and one based on afterglow light curves. This latter paper was the first prediction of the "jet break" that has become the standard tool for estimating GRB collimation.