What is an Alert Broker?
One of the results of Rubin Observatory's real-time difference image analysis processing is a world-public stream of alerts containing data about transient, variable, and moving sources (find out more about Rubin Observatory processing and products like alerts in the Data Products Definition Document). These alerts will be distributed to community brokers: software systems that will ingest, process, and serve astronomical alerts from Rubin Observatory and other surveys to the broader scientific community. Typical broker functionality includes cross-match association with archival catalogs, the identification and prioritization of objects in need of follow-up observations, and photometric classification based on light-curve analysis.
How are the Rubin Observatory Alert Brokers Selected?
Due to the anticipated high bandwidth of the Rubin Observatory alert stream, only a limited number of brokers can receive the stream directly from Rubin Observatory. The broker selection process is detailed in LDM-612; all decisions are the responsibility of Rubin Observatory Operations. In May 2019 the process began with Letters of Intent submitted from 15 teams, and in June 2019 a Community Brokers Workshop was held in Seattle, WA. In August 2019 the SAC announced that all LOI teams were encouraged to submit full proposals. In December 2020, nine teams submitted full proposals. The SAC recommendation that seven brokers receive direct access to the full stream and two operate downstream of the selected brokers was accepted by Rubin Operations.
Where can I find information about pre-LSST alert streams, real and simulated?
First, check out questions one and two of the Rubin Observatory Answers to Community Broker FAQs. For more information about ZTF alerts, see Patterson et al. (2019): The Zwicky Transient Facility Alert Distribution System. An archive of ZTF alerts made available by the University of Washington can be accessed here. ZTF alerts are being recieved, processed, and made publicly available by ANTARES (see the ANTARES FAQ and ANTARES Devkit), ALeRCE, Fink, and Lasair.
The LSSTC Enabling Science Brokers Workshop, 2020-2021
In 2020 and 2021, the Alert Brokers teams held a two-part virtual brokers workshop supported by the LSSTC Enabling Science grant. The slides, recordings, and collaborative products from this workshop are available online for Part I (2020) and Part II (2021).
