UMICH-2015: CMB-Lensing break-out session 2

Blake - CMB delensing, CMB lensing cross correlated with galaxy surveys, CMB lensing cross correlated with optical weak lensing, parameter forecasts, instrument requirements, survey requirements, systematic challenges (20 min)

Delensing Details

Blake, ~10 min, File:Delensing.pdf Delensing intro

1. When is delensing necessary?
2. Can external delensing contribute anything?
3. With delensing, is it worth having different noise levels on two different experiments (high and low-resolution)?

Questions for discussion

1. Algorithms - Quadratic Estimator / Iterative / Sampling
   • What is the best algorithm to use?
2. Systematics and Delensing
   • Dust foregrounds and sources - how do they propagate through the delensing procedure? How much do they matter?
   • Instrumental systematics, higher order biases, LSS non-Gaussianity - any concerns for delensing?
3. Analysis of Delensed Maps
   • What are the statistical and noise properties of the delensed maps? How to construct likelihoods?

CMB Lensing Cross-correlations

Blake, ~10 min, File:Crosses.pdf Questions for discussion:

1. weak lensing calibration: cross-correlations with LSST / Euclid weak lensing
   • how precise are the correlations?
   • is this level of multiplicative bias calibration interesting?
   • are intrinsic alignments a limiting factor?
2. clustering from correlations with DESI/Euclid/LSST data
   • how well can biases be modeled and constrained?
   • can dark matter clustering be recovered sufficiently cleanly to, e.g., detect neutrino mass?
   • what are the key science drivers in extragalactic astrophysics?
3. other surveys
   • would overlap with external datasets gain from a northern site?

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