DIA processing between DRP and AP will be different. Calibrations of PVIs will be better in DRP, and templates will potentially be updated. The difference will likely be greatest in the Year-One Alerts and the Data Release 1,2 processing of the first 6,12 months of the survey.
- Even meeting the same purity and efficiency requirements may not result in the same set of objects detected between AP and DRP. How much of a difference should the users expect?
- Will there be a matching between AP DIAObject IDs and DRP DIAObject IDs? Will this matching be provided by Project+Operations or will it be up to interested science groups to do this themselves?
- How will the DIAObject ID labels be different between AP and DRP. Will they be unique between AP and DRP. Will they be unique across data releases?
- Does it make even sense to refer to the set of AP DIAObject IDs “within” a Data Release? AP doesn’t formally fit into a Data Release. AP will of course be run between data releases, and it doesn’t make sense to think of AP on an image as “belonging” to a data release prior to that data. But it doesn’t clearly make sense for AP to be considered part of the next Data Release, either.
- Will DRP provide forced-photometry on all AP DIAObjects? Imagine, e.g., an object that was detected, studied, and somebody went and took a spectrum and confirmed it as an interesting FoozaWhatsIt. But imagine that in DRP, the masks are grown a bit to match where photometry and detection are more reliable and that object is no longer detected. Will this object be referred to only by its AP DIAObject ID?
- Perhaps the former question is really asking: what’s the relationship between Rubin Observatory/LSST DIAObject IDs and community transient and variable clearinghouses, such as the IAU SN, IAU MPC, or the Transient Name Server tracking?
[The intent of this topic is to summarize and generalize a discussion that occurred over Slack.]
 DRP: Data Release Processing
 AP: Alert Processing
 PVI: Processed Visit Image. Also referred to as a
 DIAObject: Difference Image Analysis Object. The result of associating individual detections on subtracted image.
 MPC: Minor Planet Center.