Mapping the Redshift Evolution of Hα Equivalent Width Distributions & RST Grism Surveys

<p>The H&alpha; Equivalent Width (EW) is an observational proxy for the specific star formation rate (sSFR) and can give us valuable insight in regards to bursty star formation histories. Studies find H&alpha; EW anti-correlates with stellar mass and increases in redshift similar to the `main sequence&rsquo; and sSFR redshift evolution. However, selection effects may bias the underlying results, such that measurements of the intrinsic correlations are needed. In this talk, I will be presenting a new methodology of constraining EW distributions by simulating emission line galaxies assuming an intrinsic EW distribution and applying selection criteria to match observations drawn from H&alpha; narrowband surveys between z ~ 0.4 and 2. This nicely overlaps with the expected redshift coverage of RST planned surveys. We find EW intrinsically correlates with H&alpha; luminosity and stellar mass, while ignoring selection effect corrections causes a steeper correlation. We also observe an increasing redshift evolution between EW and stellar mass. The correlation between EW and stellar mass is found to reproduce the EW distribution, LF, and SMF at all redshifts probed, which suggests it is shaped by physical processes associated with star formation. I will finish by discussing the implication of our results for RST survey planning by taking into account the effective EW threshold in slitless grism surveys set by the limiting resolving power using the redshift evolution of the EW &mdash; stellar mass correlation.</p>