Physical Properties of Sub-galactic Clumps at 0.5 ≤ Z ≤ 1.5 in the UVUDF

We present an investigation of clumpy galaxiesin the Hubble Ultra Deep Fieldat 05 ≤ z ≤ 1.5 in the rest-framefar-ultraviolet (FUV) using Hubble Space Telescope Wide Field Camera 3broadband imaging in F225W, F275W, and F336W. An analysis of 1404 galaxiesyields 209 galaxiesthat host 403 kpc scale clumps. These host galaxiesappear to be typical star-forming galaxies, with an average of 2 clumps per galaxyand reaching a maximum of 8 clumps. We measure the photometry of the clumps and determine the mass, age, and star formation rates (SFR) using the spectral energy distributionfitting code FAST. We find that clumps make an average contribution of 19% to the total rest-frameFUV flux of their host galaxy. Individually, clumps contribute a median of 5% to the host galaxySFR and an average of ~4% to the host galaxymass, with total clump contributions to the host galaxy stellar massranging widely from lower than 1% up to 93%. Clumps in the outskirts of galaxiesare typically younger, with higher SFRs, than clumps in the inner regions. The results are consistent with clump migration theories in which clumps form through violent gravitational instabilitiesin gas-rich turbulent disks, eventually migrate toward the center of the galaxies, and coalesce into the bulge.