The Extended LSST Astronomical Time-series Classification Challenge (ELAsTiCC)

The Extended LSST Astronomical Time-series Classification Challenge (ELAsTiCC) is a real-time test of Rubin community- and science collaboration readiness. Over three months, we will stream a simulation of 139,106,486 observations of 4,328,315 objects from the Legacy Survey of Space and Time (LSST) to 5 of the seven Rubin-selected community brokers. These brokers will process the alerts using a mix of community-contributed and internally-developed algorithms, attempting to put alerts into a rich taxonomy, and return results to the LSST Science Collaborations. Our simulation includes 30 models, including predicted events that have never been observed, and our alerts include, for the first time, realistic associations between transient and variable objects and their host environments, as well as photo-z information. Unlike its predecessor, PLAsTiCC (Kessler et al. 2020, Malz et al. 2020, Hložek et al. 2022), we also include several different metrics to characterize the performance of algorithms and brokers. I will provide a broad overview of the challenge along with details on how to get involved and engage with the data, as well as initial results and takeaways from our experience.