Welcome, Introductions, Goals, Charge

• Suzanne Staggs (Princeton University)
• John Corlett (Lawrence Berkeley National Laboratory)

Measurement Goals & Science Requirements *SO Point of Contact: Jeff McMahon jeff@astro.uchicago.edu CMB-S4 Point of Contact: John Carlstrom jc@kicp.uchicago.edu* **Charge:** - Compare the use of SO and ASO with the CMB-S4 baseline to meet science requirements. - Are the current estimates of using ASO to replace a CMB-S4 CHLAT/ LATR good enough or is more simulation/estimation needed to show scientific performance? - Compare the map depth estimates from the two projects from their currently planned surveys. - Also provide a simplified analysis based on comparing estimates of target sensitivities for single detectors in each band for the SO LATR versus the CMB-S4 LATR, combined with adjustments for survey sizes and durations. - Are the scan strategies for the two projects (for LATs in Chile) aligned, regarding cadences for time domain targets? - Describe the benefits to CMB-S4, and particularly to the time domain community, for continued operation of SO between the start of SO operations and the start of CMB-S4 operations, if the ASO MSRI-2 proposal is not funded.

LAT& LATR & DAQ WG *SO Point of Contact: Mark Devlin devlin@physics.upenn.edu CMB-S4 Point of Contact: Mike Niemack niemack@cornell.edu* **Charge:** - Is CMB-S4’s current observatory control plan capable of controlling the SO LAT and monitoring its environmental sensors or is additional work needed? - Is CMB-S4’s current observatory control plan capable of controlling and monitoring the SO LATR? Is it capable of controlling and monitoring SO SATs? - Is the SO LAT totally compatible with the S4 LATR or are changes needed? - Provide a ROM estimate of the time and cost to switch from the SO LATR to the S4 LATR. - Describe any existing coordination activities between the projects related to the LAT and LATR? Are there additional areas where additional early coordination between the projects would be mutually beneficial? Do any of these impact CMB-S4 design decisions?

Site WG *SO & CMB-S4 Point of Contact: Kam Arnold ksarnold@physics.ucsd.edu* **Charge:** - Are there site or infrastructure modifications that would be needed to enable use of the SO LAT, with or without its LATR, by CMB-S4? - What steps are needed to enable use of the ASO PVA by CMB-S4? - Are there areas where additional early coordination between the projects would be mutually beneficial? - Are there conflicts between CMB-S4 planned site operations and SO/ASO operations?

Data Management WG

• Simone Aiola (Center for Computational Astrophysics, Flatiron Institute)
• Julian Borrill (Lawrence Berkeley National Laboratory & UC Berkeley)
• Laura Newburgh (Yale University)
• Jo Dunkley (Princeton University;)

*SO Point of Contact: Jo Dunkley jdunkley@princeton.edu CMB-S4 Point of Contact: Julian Borrill jdborrill@lbl.gov* **Charge:** - Are there major systems or requirements that differ significantly, and/or are in conflict between the two projects? (E.g., file formats, data registration system, site computing, requirements on how soon data are made public). - Are existing DM frameworks generalized enough to accommodate each other? Outline where the interfaces would lie between the two projects that would enable their disparate raw data to be handled in the DM pipelines. - Are the requirements for time domain / transient data products aligned? Suggest steps to coordinate time domain DM efforts. - Is CMB-S4’s site computing and data transport plan consistent with use of the SO LATR? With the use of the SO SATs?

Next Steps

• Suzanne Staggs (Princeton University)
• John Corlett (Lawrence Berkeley National Laboratory)