Let's Go Extreme with Roman: Observing z ~ 0. 5 – 2 low and high EW ELGs

Planned grism surveys with Roman will shed much light on star formation histories of galaxies near cosmic noon. Hα Equivalent Width (EW; observational proxy for specific star formation rate; sSFR) is one tracer of episodic SF activity. In this talk, I will present a new methodology of constraining intrinsic z ~ 0.4. – 2 EW distributions, show how past measurements of EW – stellar mass trends and redshift evolution are selection biased, how our approach resolves the disagreement between observations and simulations of the cosmic sSFR evolution, and highlight our measured intrinsic EW(M,z) correlation. We find high EW (sSFR; bursty SFHs) Hα emitters are numerous and important contributors to cosmic star- formation activity at z > 1.5. Recent JWST studies (e.g., EIGER) find numerous high EW emitters at EoR with extreme ISM conditions and star-formation. Past studies also find EW correlates with ionizing photon production efficiency. Including our results, this suggests high EW emitters play a major role in cosmic SF and may be analogs of high-z ionizing sources at EoR. Finally, I will discuss how we can observe typical and high EW ELGs with Roman grism by using our EW(M,z) to predict number counts and range of EW and stellar mass.