Telecon Notes 20171101

Attendance: Raphael, Amy, Shaul, Al, Eric, Brendon, Nick, Charles, Lloyd, Jamie

Notes by: Karl

• Brief: authorship policy on papers/abstracts
• Update from Fundamental Physics Group (Raphael)
• Spectrometer/Imager discussion

Authorship policy on papers/abstracts

• Shaul: proposal, for each abstract poll EC and relevant WGs. People then ask to be included.
  • Raphael: just small group on abstract? or endorsers as well?
    • Shaul: these are just updates, not final word. so endorsers not needed. Will be needed for final report.
• No objections.

Update from Fundamental Physics Group (Raphael)

• comparing low-res and hi-res cases (140cm vs 50cm)
• forecasts with foregrounds. synchrotron from WMAP/Planck. dust is 2-component Finkbeiner.
  • no frequency decorrelation between foregrounds
• foreground removal via minimum variance ILC
• done for polarization
• more work to extend to r. as foregrounds have larger effect. Need more tools for that estimation.
  • current presentation is signals in T and TE.
  • Shaul: also calculate r limits with no foregrounds, for reference.
• parameter forcasts done.
  • all at 70% of sky. CL: this is reasonable.
  • for LCDM, 2 cases very similar
  • LCDM + X, goes from competative with S4 (Neff) to not. 140 cm to 50 cm.
    • Neff is large sacrifice. Neff is at 70% of sky
  • delensing also worse with lo-res.
    • hi-res has A_lens 17%, lo-res is ~ 2x higher. still running.
• large mission needed to do delensing and Neff in PICO.
  • Charles: a probe mission needs to be able to do all analysis with its own data. Not relying on other data sets that are lower quality.
  • Raphael: if combining with S4 noise is likely ok, but S4 has less sky coverage.
  • Amy: risk in proposing with dependency on other data.
    • Shaul: saying PICO only worth pursuing after data sets PICO depends on are complete or nearly so.
• Shaul: PICO small, like LITEBird, foreground cleaning method unclear. Would need a way to say small experiment looking at reionization peak can put low limits on r.
  • Al: could do imager at < 200 GHz for low foregrounds and reionization peak. plus spectrometer for high frequency. does high frequency from space.
    • Raphael: could be good straight B-mode mission.

Spectrometer/Imager discussion (continues above suggestions)

• Shaul's science matrix. in process. Goal: capture science of imager and spectrometer. missing galactic science
• spectrometer science
  • Al: constraints on mu with no detection are still useful. best limit on primordial spectrum and running. also give probe on light DM canidates via their annihlation.
  • remove foregrounds, some doubt this is the method needed. Al convinced spectrometer is needed.
  • CIB – get evolution of star formation and cold gas. mini-PIXIE does this in CII, some CO transitions.
    • Shaul: quantify S/N. explain measurement, analysis, which constrains . Provide this story for final table.
      • Eric: this is being worked on in community. process is still evolving in field.
      • Jamie: at low redshift, can this be done with big beam?
        • Eric: must cross correlate. probes linear scales which is good. Will think more about science case story.
        • Shaul: hard for an evolving method to be a strong science driver.
• Imager science:
  • fundamental physics (see Raphael's presentation),
  • extra-galactic science (in process). hi-resolution important for these point sources.
  • galactic science to be added (also discussed in past telecon)
• General discussion:
  • Al: pixie review comments,
    • panel didn't see need for space was compelling. if ground based observes r first, then PIXIE isn't worth it.
    • Jamie: was this because PIXIE wouldn't give the definitive measurement? As was done for past CMB observables.
      • Al: not clear.
      • Lloyd: reviewer missed something. we need to communicate context better in case when mission follows a ground based detection.
      • Al: seems that NASA perception is once B-mode detected no further work is needed. Alternative argument needs to be made clearly.
    • Shaul: panel questioning if inflation is a 1 number science ®. need to address this for imager or spectrometer PICO. Could avoid by proposing Super-PIXE and get other observables as focus.
      • Jamie: if spectrometer can test inflation from different observables that is a nice story.
        • Shaul: not clear that small PIXIE can do this. so not so exciting.
        • Charles: agree. big spectrometer is more interesting. Responding to 'are you done if r measured from ground? Imager gets r and tau. Many experiments assuming tau, but need space to measure this. r and tau measured at level unachievable from ground are enough to justify probe. The rest is gravy.
          • Al: that's what PIXIE promised, but wasn't selected.
    • Lloyd: what about pushing on broader anisotropies questions?
    • Charles: having 1 primary goal + bonus has been a better pitch.
    • Lloyd: if r is detected, then push to map power spectrum to reionization peak, needed to see scale invariant spectrum to largest scales. The confirmation itself is important, mapping the power spectrum.
      • Raphael: not sure there are models that do this. reionizaiton bump useful to measure spectral index.