2024-04-22 DM-SST Agenda and Meeting Notes

Short : ls.st/dmsst 

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Report from PST presentation on PHAs.

• Discussion was around using Rubin embargoed data to detect PHAs early to reduce uncertainty in orbit predictions. The scenario whereby  we discover a fast object consistent with being an impactor but the uncertainty is large. Access to detections on previous night make the orbit predictions more accurate => forced photometry on Rubin embargoed images to look for detections at 2/3 sigma on previous nights.
• Think this is about a few objects per year. 
• Orbit calculation is done by MPC + JPL – these are the teams best placed to handle planetary defense. 
• There is a group at JPL with all the necessary clearances to access the relevant  government assets catalog – they are interested in having anything from access to forced-photometry on embargoed images to the maximal scenario whereby we give them access to all images and they run specialized software for PHA. Need to ask OGAs is this is a feasible scenario
• Action – Zeljko to ask at the next JOG meeting to have Ed Ajhar to talk to Ashley (liaison to OGAs) to ask which data access scenario they prefer. 
• Action – Steve will ask Mario about the probability of the scenario whereby 

Report from PST - SC chairs meeting

AGN – slide link

• Asked "How to add members in bulk to SC group on the Community platform" (with and without existing accounts
• DCR information – they hear that there will be some provided but what exactly and what the mechanism is. What they need is enough information to simulate LSST DCR values for known objects (ideally from their data challenge data set) and begin training selection/classification/photoz algorithms.
• The DCR information they want is detailed in 2 papers from Gordon Richards
  • https://docushare.lsstcorp.org/docushare/dsweb/Get/Document-30573/richard_dcr_wfd.pdf
  • https://docushare.lsst.org/docushare/dsweb/Get/Document-37642/Differential_Chrom_Refr.pdf
  • TVS also commented that  DCR is relevant for TVS too and they worked witn DM members on this paper https://arxiv.org/abs/2402.06002
  • What documentation exists on DCR and the information available?
• Several in-kind contribution teams working with AGN-SC. What support if any will be available to integrate products back into the DM system

SMWLV – slide link

• Asked "What precursor datasets are appropriate for globular cluster detections (out to EG distances)? Does DP0 have relevant data for this?". LPG pointed them to source injection code and stated that DP0 is now closed.
• Directed them to the Rubin Science Assemblies. Kristen Dage noted that " some of my students attend these meetings (Rubin Science Assembly) and love them. Everyone seems to be interested in source injection."

TVS – slide link

• Need for more light curves for stellar science/variable stars in DP0- again, pointed them to source injection. 
• Challenge of "Transition towards using real data, alert streams via brokers" noted 

Do we have source injection tutorials?

• Mario and Z meeting with agencies to day to discuss this topic. No other progress yet. 
• DCR  - SED corrected photometry has been promised but not done 
• Analogous to SN photometry question

Re. Forum-related question from AGN SC

• Added "How to add Forum group members in bulk" drop-down FAQ to the topic "How to use the Forum as Science Collaboration chair" which was recently circulated to all SC chairs.

yes we have source injection tutorials

Geosynchronous satellite, NASA + NIST, PI Plavchan.

• Has a number of NIST-calibrated wavelengths ("very narrow", don't know how narrow exactly), emitted to earth. With well-measured flux on the satellite. "top of the atmosphere" source.
  
  • at least one in each relevant band. Want to get ugrizy coverage.
• + possibly a mirror that reflects the sun to the ground, sometimes. Has to be streaks for us.
• ETA ~5 years to launch.
• Orbital inclination? Eli thinks zero. Longitude, somewhere in western hemisphere, visible from HI, AZ, CL.
• What to do for next steps? Need some formal channel for project-to-project communications, what wavelengths we prefer. What about getting permission to observe geosync? (in non-sidereal)
  • Arrange a talk either to SST or PST?
  • Ask Steve Ritz to help arrange. Maybe a more public venue? PST talks are recorded, could make that available. Not a DESC topic, broader than that.

• Current draft https://dmtn-228.lsst.io/v/DM-34512/index.html
• "Pre-defined set of points (areas) where <5 sigma alerts are permitted"
  
  • e.g. GW followup in TOO, "Gravitational Keyholes" for asteroids.
• Regular alert stream? Some end-of-night product? Does this impact the latency of the regular-threshold-alert? Can we defer this for post-year one?
• Gregory: original motivation for writing the requirement was QA, so one can understand the impact of the selection criteria. DMSR requirement does not say that alerts must be sent, but DPDD does say alerts. Points towards this being ok to deliver later after the start of the survey.
• Jim: Strong lensing is pushing for this, want to find lensed objects early. Looking along the caustic where you might find SNe. If it's small area, people could look for the SNe/KNe themselves, but they can't because of the embargo.
• Users need pixels, so making these part of the alerts is good.
• Aim for a statement at community workshop.

Expect RSP to be on the agenda for #2 and #3, both not earlier than CY2025. Have to decide what of the RSP requirements is on the hook for those reviews.

• July 15th, DM-SST vF2F. Week after DESC, week before RCW.