0 Assigned ID: 2154 ----- Attempting Submission 1 (Fri Apr 09 19:37:14 GMT 2021) ----- HST Phase I Proposal 2154 successfully submitted. Receipt: # 2154-1 ----- Attempting Submission 2 (Fri Apr 09 21:14:47 GMT 2021) ----- Understanding the reionization of the universe is a major focus of upcoming ground- and space-based facilities. One major source of uncertainty is the escape of hydrogen ionizing (LyC) photons during the epoch of reionization (EoR). This quantity *cannot* be measured at z>6, so local indirect indicators are being calibrated using local galaxies. HST has invested hundreds of hours in the effort of 1) identifying LyC emitters and measuring their escape fraction of LyC radiation (fesc), and 2) calibrating indirect estimators of fesc to use at z>6. Among the various indirect tracers of fesc, Lyman alpha (Lya) and Mg II promise to be the most informative, as they carry information about the density, velocity and distribution of the neutral gas. What is missing, and what we are proposing here, is a full modeling effort to link Mg II emission to Lya and LyC, properly accounting for the nebular emission and the continuum scattering component. Specifically, we will 1) perform detailed radiation transfer calculations of the propagation of Mg~II and Lya through the interstellar and circum-galactic media, for general geometries and velocity fields. These models will be 2) used to infer the neutral gas properties in confirmed LyC emitters identified by local Hubble surveys. In addition to interpreting Hubble data, our work will be crucial to make the most out of upcoming JWST programs that will observe EoR galaxies in Lya and MgII to estimate fesc and, ultimately, constrain the EoR. We will make our calculations publicly available as a resource for the community to interpret JWST observations by early 2022. Team members offer expertise on all relevant skills for a successful completion of the program. On the modeling side: Carr, Scarlata, Verhamme, Blaizot, Michel-Dansac have developed SALT and RASCAS and are experts on the modeling of absorption line spectra in galaxies. On the data side: the team includes a large fraction of the Local-Redshift Lyman Continuum Survey (LzLCS). Scarlata, Schaerer, Borthakur, Chisholm, Jaskot, Hayes, Henry, Scarlata, Schaerer, Flury. Henry, Borthakur, Scarlata and Schaerer are conducting the followup for MgII observations. Intergalactic Medium and the Circumgalactic Medium 0 Regular false false true true false SUPPORTED