0 Assigned ID: 682 ----- Attempting Submission 1 (Fri Apr 11 18:53:11 GMT 2014) ----- HST Phase I Proposal 682 (ff_archive.apt) successfully submitted. ----- Attempting Submission 2 (Fri Apr 11 21:49:10 GMT 2014) ----- HST Phase I Proposal 682 (ff_archive.apt) successfully submitted. ----- Attempting Submission 3 (Fri Apr 11 22:34:28 GMT 2014) ----- HST Phase I Proposal 682 (ff_archive.apt) successfully submitted. ----- Attempting Submission 4 (Fri Apr 11 23:07:18 GMT 2014) ----- HST Phase I Proposal 682 (ff_archive.apt) successfully submitted. ----- Attempting Submission 5 (Fri Apr 11 23:53:07 GMT 2014) ----- Using the magnification provided by gravitational lensing, our team has recently uncovered an important population of star-forming dwarf galaxies at 1<z<3.5. Both the star formation histories and the dust extinction properties in these galaxies are claimed to be significantly different from their more massive counterparts, but uncertainties remain. First, the star formation rates of these dwarf galaxies are expected to vary by an order of magnitude on short, 10-30 Myr, time scales unlike the more massive galaxies. Second, the dust extinction is claimed to be very low, but these claims have not considered that the intrinsic colors of these galaxies are likely very different than more massive galaxies. In cycle 21, we were awarded 48 orbits of near-UV imaging of the three best Frontier Field cluster lenses to measure the ultraviolet properties of a large number of star-forming dwarf galaxies. Also in cycle 21, the GLASS survey was allocated 140 orbits of WFC3/IR grism spectroscopy of 10 lensing clusters, including 42 orbits of spectroscopy in the Frontier Fields for which we have near-UV imaging. We propose for archival funding to incorporate the WFC3/IR grism spectroscopy of a sample of ~70 dwarf galaxies at 0.75<z<1.5 in the three Frontier Fields with deep near-UV imaging. Together, the UV and H-alpha luminosities will determine star formation rates on very different timescales, allowing us to quantify the "burstiness'' in these dwarf galaxies. Furthermore, both the UV spectral slope and the Balmer decrement (Halpha/Hbeta ratio) will allow independent measures of dust extinction, to better quantify the intrinsic star formation rates in these galaxies. UNRESOLVED STAR FORMATION Default Medium false true false false false SUPPORTED