The Hourglass Simulation: A Catalog for the Roman High-Latitude Time-Domain Core Community Survey*

We present a simulation of the time-domain catalog for the Nancy Grace Roman Space Telescope's High-Latitude Time-Domain Core Community Survey. This simulation, called the Hourglass simulation, uses the most up-to-date spectral energy distribution models and rate measurements for \ntrans extra-galactic time-domain sources in addition to a fixed luminosity source. We simulate these models through the current baseline Roman survey: four filters per tier, a five day cadence, over two years, a wide tier of 19 deg² and a deep tier of 4.2 deg², with ~20% of those areas also covered with prism observations. We find that a general time-domain catalog, assuming a S/N at max of >5, would have approximately 25,000 Type Ia supernovae, 70,000 core-collapse supernovae, over 70 superluminous supernovae, ~40 tidal disruption events, 5 kilonovae, and possibly the first confirmed detection of pair-instability supernovae. Hourglass is a useful data set to train machine learning classification algorithms. Additionally, we present the first examples of non-Type Ia supernovae spectral-time series data from Roman's prism.