UMICH-2015: Dark Energy / Gravity / Dark Matter break-out session 3
From CMB-S4 wiki
- What frequency coverage, angular resolution and fsky is required for each one of these probes?
- How to implement proper forecasts (dealing with systematics, parameters space to explore...)
- How these probes compare to others (e.g. future galaxy surveys) in terms of constraints?
Diffuse SZ effects/ Mapping momentum (lead by Francesco De Bernardis):
- Constraining reionization with kSZ power spectra: see for example recent forecasts in http://arxiv.org/abs/1406.4794.
- kSZ pairwise statistics: promising with current data. It should be very powerful with CMB-S4. File:CMB-S4 ksz.pdf. See also http://arxiv.org/pdf/1412.0592.pdf - http://arxiv.org/pdf/1408.6248v1.pdf
- kSZ via cross correlation with reconstructed velocity fields. As above, it's already promising with current data, compelling in the future.
- Separating tau/v/T_e. Forecasts: What channels are most important? How much is limited by sub-mm emission? What are realistic priors (on T_e for example) from future x-rays missions?
- SZ polarization: offers another way to constrain clusters optical depths. Plus several other nice things: CMB quadrupole vs redshift for example. The signal is small (~0.1 uK at the center of very massive clusters) but stacking approaches might work.
- K. Huffenberger: old poster with some estimates for stacking for quadrupole
- SZ polarization from transverse motion of clusters: sensitive to the transverse component of the velocity field (hence, complementary to kSZ). Potentially very interesting but even smaller than the previous effect: suppressed by (v_t/c)^2. It should have a different frequency dependence though.
Dark Matter (lead by Cora Dvorkin):
- How do forecasts on Dark Matter annihilation change when including foregrounds? (The current constraints do not include any foreground contribution).
- How much can we tighten the constraints on <sigmav>/m by adding prior information on As from other observables?
- What other dark matter scenarios can we learn about from the CMB (aside from WIMP dark matter annihilation)? (baryon/dark matter interactions, a complex dark sector, dark matter scattering with neutrinos, other models?)
- What are the degeneracies with other non-standard cosmological parameters (i.e., Neff, neutrino mass)?