0 Assigned ID: 22 ----- Attempting Submission 1 (Fri Feb 21 18:05:11 GMT 2020) ----- HST Phase I Proposal 22 successfully submitted. Receipt: # 22-1 ----- Attempting Submission 2 (Fri Feb 21 18:12:22 GMT 2020) ----- HST Phase I Proposal 22 successfully submitted. Receipt: # 22-2 ----- Attempting Submission 3 (Fri Feb 21 19:02:07 GMT 2020) ----- HST Phase I Proposal 22 successfully submitted. Receipt: # 22-3 ----- Attempting Submission 4 (Fri Feb 21 19:10:32 GMT 2020) ----- HST Phase I Proposal 22 successfully submitted. Receipt: # 22-4 ----- Attempting Submission 5 (Sat Feb 22 01:56:54 GMT 2020) ----- HST Phase I Proposal 22 successfully submitted. Receipt: # 22-5 ----- Attempting Submission 6 (Wed Mar 04 03:30:59 GMT 2020) ----- HST Phase I Proposal 22 successfully submitted. Receipt: # 22-6 ----- Attempting Submission 7 (Fri Mar 06 02:25:33 GMT 2020) ----- HST Phase I Proposal 22 successfully submitted. Receipt: # 22-7 ----- Attempting Submission 8 (Fri Mar 06 18:58:40 GMT 2020) ----- Dust is pervasive in high redshift galaxies, and assumptions about how it attenuates starlight and impacts conditions in the ISM strongly affect conclusions on the intensity and history of star formation for these galaxies. At present, these model assumptions are underconstrained using data obtained with HST and Spitzer. We propose to test whether the key standard assumption made in modeling high redshift galaxy (z>6) rest-frame UV spectral energy distributions - that high-z galaxies lack a significant 2175 Angstrom Bump feature - is valid. We will use deep archival HST near IR grism spectroscopy to make the first direct spectroscopic census of the 2175 Angstrom bump in 2<z<4 galaxies. Our analysis will provide a novel assessment of the nature and evolution of dust in these galaxies, allowing us to better understand how star formation can modify dust in the ISM. Specifically we will: 1) Detect and measure the 2175A Bump profile for a large (~800) sample of 2<z<4 galaxies; 2) Determine the most appropriate dust attenutation models for these objects, incorporating, for the first time at this redshift, both rest-frame UV spectroscopy and optical broadband imaging; 3) Re-derive stellar population parameters (Age, Mass, Star formation intensity and history) corrected for attenuation, for individually detected 2175A host galaxies and for relevant subsets of galaxies; and 4) Re-assess popular proxies for LyC emissivity that rely on (under-constrained) measurements of UV continuum. The Proposal team consists of individuals with 1) extensive backgrounds in the reduction and analysis of grism spectroscopy, 2) the analysis of UV-optical-Near IR spectroscopy and SEDs of local and high redshift galaxies using a wide range of proprietary and public software tools, and 3) surveys of LyC escape in the local and high redshift galaxies using multiple generations of UV observatories, and the theoretical understanding of the mechanisms for its escape. Specific references are provided as follows. PI Rutkowski has extensive experience in the study of LyC escape from SFGs at z>1 using HST (WFC3, ACS/SBC), GALEX, and AstroSat. He has managed projects which used the HST IR grism modes for restframe optical emission line spectroscopy. He was an affiliate member of the WFC3 ERS team and has also extensive experience in studying recent star formation in ETGs. Dr. Battisti is an expert in characterizing the dust attenuation of galaxies, galaxy SED modeling, and combining legacy archival datasets for use in studying galaxy evolution. Dr. Cohen has over 20 years of experience in studying galaxies with HST, including a detailed understanding of grism data and the analysis of broadband and spectroscopic UV-optical observations of AGN, SFGs, and UV-bright galaxies. Prof. Eskridge has 20 years of experience in studying nearby galaxies in the near UV using IUE and HST. Dr. Jansen has over 18 years of experience analyzing HST data from FOC, STIS, WFPC2, ACS, and WFC3, studying galaxy assembly and evolution from the early universe to the present, with an interest in extinction by interstellar dust, as well as various technical aspects of HST data reduction. He is PI of Cycle 25 program GO15278 to image the JWST NEP Time-Domain Field, and Co-I of JWST GTO program #1176. Prof. Malkan is an expert on slitless HST grism spectra, having been PI on many proposals doing this with more than one instrument, in hundreds of different fields. He has also used emission line and continuum measurements to study galaxy reddening over many decades. Dr. Ryan has over a decade of experience in the reduction and analysis of ACS grism observations for the study of emission line galaxies and absorption lines of brown-dwarf stars. Dr. Ryan is the author of the LINEAR grism reduction software package. Prof. Scarlata is an expert on the properties of Lyman alpha and UV diagnostics associated with star formation and LyC leakage in high specific SFR galaxies and Green Peas. Together, Drs. Rutkowski, Malkan and Scarlata have extensive experience in the analysis of rest-frame optical characteristics for star formation, as observed via HST grism surveys. Prof. Windhorst has been working on and with HST since 1986. Interdisciplinary Scientist for JWST since 2002. Starting in 1998, he was an active member of the WFC3 SOC, with a keen interest in designing and using the WFC3 UV filters. Expert in distant galaxies and cosmology. Mr. Jeon is a Spring 2020 undergraduate of Arizona State University. He is currently studying the rest-frame SEDs of high redshift (5<z<7) star forming galaxies observed by HST & Spitzer. Galaxies 0 Regular false false false false false SUPPORTED