Early Science

"Early Science" is defined as any science enabled by Rubin for its community through and including the first data release, Data Release 1 (DR1). This includes the commissioning period and the first year of survey operations.

The Rubin early science program is described in full in the Rubin TechNote RTN-011: Rubin Observatory Plans for an Early Science Program, which has a citable DOI for grant proposals.

Questions? Everyone is invited to post their questions as a new topic in the "Early Science" category of the Rubin Community Forum, where it will be seen and responded to by Rubin staff.

Below, a very brief overview of the planned early science program for Rubin Observatory is provided.

Motivation: Rubin Observatory has created a plan for an early science program in order to enable the science community to:

1. accomplish high-impact science as soon as possible
2. have early access to both static-sky and time-domain science-ready data products
3. conduct time-domain astronomy research via Alert Production

Data Previews: A series of Data Previews (DP) based on commissioning data are planned to support the community as they develop their LSST analysis software and workflows, and to enable high-impact science as soon as possible.

• Data Preview 0 (DP0) is based on simulated LSST-like data. DP0.2 was released in June 2022, and DP0.3 in July 2023. Instructions for accessing DP0.
• Data Preview 1 (DP1) will be based on a few nights of data from ComCam or LSSTCam (TBD Feb 2024) and is expected by Jul 2025.
• Data Preview 2 (DP2) will serve a full reprocessing of all science-grade LSSTCam images obtained before survey operations, and is expected by May 2026.
• Data Release 1 (DR1) will be based on the first 6 months of survey operations and is expected by Jan 2027.

Template Generation: Due to the need for templates derived from a data release, Alert Production cannot run at full scale nor full fidelity prior to DR1. In order to provide early access to time-domain data products and enable time-domain science, there is a plan for template generation prior to DR1.

• Generate templates using LSSTCam commissioning data in order to maximize the area covered by templates and available for Alert Production at the start of survey operations.
• Generate additional templates incrementally, and immediately use them, during the first year of survey operations (when a sufficient number of images that pass quality cuts have been acquired).

Survey Strategy: The Survey Cadence Optimization Committee (SCOC) will make specific recommendations for these early survey observations (e.g., prioritization of sky area coverage). Producing a meaningful and informed recommendation that can be implemented effectively requires the SCOC to interact closely with the Rubin Commissioning and Operations teams. To allow time for those interactions the Early Science recommendations are deferred.

Data Products: A summary of the expected early science data products that would be available as part of DP1, DP2, and DR1 can be found in Table 1 of RTN-011. Although there remains a siginficant degree of uncertainty in the DP1 data products, the minimal set to expect includes processed visit images and associated catalogs. For DP2 the data products will include processed, coadded, and difference images and the associated catalogs of measurements for sources detected in those images. During commissioning, the aim is to begin routine Alert Production as soon as is feasible (maybe with higher latency; see Section 4 and Table 2 of RTN-011). General information about the data products that Rubin Observatory will and will not provide in future data releases is provided in "Rubin Data Products -- Abridged".

Early Science Scenarios: Understandably, there remains some uncertainty in the exact timescales and for the Rubin commissioning phase. There are two scenarios, but importantly, the contents of DP2 will be the same irrespective of which scenario materializes. Only the timing of the DP2 release and the start of survey operations are different. More information about these scenarios is available in Section 1.4 of RTN-011.

• Scenario A: The commissioning and science validation (SV) surveys are executed as planned, the Operations Readiness Review (ORR) succeeds in demonstrating readiness for the start of the 10-year survey on time. The SV survey data are reprocessed to produce DP2, which is released 6 months following the completion of the SV survey.
• Scenario B: On-sky time in commissioning is reduced as the construction work draws to an end without the completion of the SV survey. The Operations team spends up to 3 months prior to commencing the 10-year survey carrying out the remaining SV survey observations. The SV survey data are reprocessed to produce DP2, which is released 6 months following the completion of the SV survey.