Lya Emitters at Cosmic Dawn with a Deep Roman Grism Survey
Lya surveys are an important tool to constrain the timing and topology of reionization. However, ground based Lya surveys are not effective at z>8 largely due to the increasing night sky background, and even at z~7 Lya surveys must conduct expensive spectroscopic followup of their Lya candidates to eliminate contamination. The Roman Space Telescope’s ability to obtain deep near-infrared spectra over a wide field of view offers the opportunity to revolutionize this field. To investigate this further, we have simulated a deep multi-position-angle Roman WFI grism survey and tested our ability to recover z>7 Lya emitters. Our initial simulations indicate that we can achieve the sensitivity required to constrain the ionization state of the z>7 intergalactic medium with Lya luminosity function tests. I will discuss our latest higher fidelity simulations and how our ability to recover high-redshift Lya emitters is altered.