Abstract

Recent discoveries of small lensed star clusters have pushed the limits of scales we can observe with the power of gravitational lensing. I will present RELICS observations of the highly magnified Sunrise Arc, a 15" long lensed arc observed at z = 6.2. This arc hosts multiple images of a star cluster with radius r < 10 parsecs, the smallest yet measured at z > 1. Besides this most prominent feature, the arc contains six other clump structures, including what appears to be a core at the center of the galaxy. The impressive magnification of this arc will allow us to study this reionization-era galaxy in exceptional detail, and it will be an excellent target for the upcoming JWST.