Roman CCS White Paper: Options to Increase the Coverage Area of Prism Time Series in the High-Latitude Time Domain Core Community Survey

The current reference High-latitude time domain survey increases the completeness of transients with prism temporal time series data by adjusting the ratio of prism-to-imaging time. However, there are two other nobs that allow for a more complete prism coverage: prism cadence and exposure time. In this white paper, we discuss how changes to the prism cadence and exposure time – in order to increase the fraction of observed transients with spectral time series – affect supernova cosmology, transient typing and template building, and the study of rare transients.