Description
The Vera C. Rubin Observatory will commence the 10 year Legacy Survey of Space and Time (LSST) this year in 2025. Within 60 seconds of the shutter closing LSST will issue rapid, public alerts of transient sources found in each visit. To detect these sources templates of the static sky are required to conduct difference imaging. However, in Year 1 of LSST the sky is visited for the first time and templates must be generated as the survey progresses, which will limit the visits able to produce alerts. We have assessed the effects of template generation using the Metric Analysis Framework and the latest survey simulation (one_snap_v4.0_10yrs). We focus on discovery metrics for Solar System Objects (SSOs) and find that the ability of LSST to discover SSOs in real-time is greatly reduced when template generation is required. Sky regions that are scheduled to receive fewer visits, such as the North Ecliptic Spur (NES), or filters that are less frequently sampled (e.g. u and g), show the greatest loss of alerts. Relative to the baseline survey strategy, up to 79% of Main-Belt asteroids in the NES will not receive real-time discovery alerts. These alerts are not lost per se as all visits will be reprocessed in subsequent data releases; but the opportunities for rapid follow-up observations will be greatly reduced. This is particularly relevant for discovery of potentially hazardous asteroids and interstellar objects, but the lack of real-time alerts is sure to have an impact on many other LSST science goals.
