Baseline sensitivities and frequencies exist for the Imager
Working groups working on making first forecasts with baseline sensitivies, and providing guidance on measurement requiremetns
WGs also beginning to work on filling out their parts of STM
Results of these activities due end of September
Charles mentions we don't have what we need for foregrounds, for all-sky.
Charles says most important question is, how do we get sufficient angular resolution at low frequencies? Points out that in S4 forecasts we are seeing impact of low-frequency poor resolution.
LK to contact Kovac regarding optimization across bands.
Al pushes back on Charles's pushing this question as the primary question. Should address: raw sensitivity, systematics, and the ability to remove foregrounds. We should not over-emphasize any one of these. Target audience does not care. Target audience is a much broader community. We need something plausible to them.
Charles: Here's a number for 3 or 10 deg patches of sky for judging plausibility: difference of having high ang. res for at least one low-freq channel and not, was a factor of five in the level of foreground residual power.
SH: we are using a 3m dish in baseline, so 21
GHz beam size is fwhm=41'.
LK: that might be sufficient. 40
GHz would be 20', below the 26' that Raphael used as “high-res”
SH: We might go back to Cross-Dragone. Would preserve effective aperture size.
Spectrometer
Decision point on whether to include has to be on October 11.
What are implementation tradeoffs? Shaul's slides show imager (shrunk down to Litebird size) plus a spectrometer box inside launch envelope.
This is just a geometry check. Does it fit in the volume? No check on e.g., power, cost.
SH: Amy has a cost assessment that shows the imager would have to shrink down to “nearly Litebird size pretty much.” To understand this well enough to make a decision the engineering to figure out would require immediate Goddard support.
AK: WE can get some engineering support from GSFC, particular in next couple weeks before fiscal year runs out.
SH: Important question: what is the scope of these two instruments? We want to be able to have an informed discussion for the EC prior to October 11 decision time. Next week Al will present to us the science case for a smaller than half-meter aperture spectrometer.
AK: Colin Hill will put together a talk for this.
Colin isinvited to attend and is available.
Instrument Design
Cost model is built
Kris is working on scan strategy. SH says going slower than he had hoped it would go. Will touch base again with Kris this week. We may want to engage other people who have more bandwidth and time for this.
CL: Talk to Kris. Let me know if it looks like there's a problem there.
Workshops: FG workshop
not happening! LK and JB to try to get SOC for the meeting together and operating
SH: we will need to decide aboout spring possible CMB-S4 joint workshop in November.
LK: S4 might be ready to deal with that then, post SOC–> ICCC phase transition with some time for settling down.
SH: data challenge very important!