kSZ 4pt analysis using SPT x SPIRE

Paper:

• Raghunathan S., SPT-3G and SPTpol Collaboration 2024; arXiv:2403.02337.

Overview:

• This work uses a quadratic estimator, similar to CMB-lensing, to reconstruct the velocity-induced correlations on large-scales of the small-scale kSZ signal.
• The method is based on Smith & Ferroro 2016(arXiv:1607.01769).
• Given that the reionisation process is expected to be patchy, it should give rise to non-Gaussian kSZ signals.
• The trispectrum measurement will help us to differentiate between the contributions from the reionisation and the post-reionisation (due to haloes in the local Universe) kSZ signals which are hard to de distinguished in the power spectrum space.

Results:

• read_files_and_make_plots.ipynb: Reproduce plots in the paper.
• K_map_data_sims_meanfield.npy: Reconstructed $\hat{K}(\hat{n})$ map from simulations.
  • Note that the data map is currently not released.
  • Used for Figure 1 of the paper.
• CL_kk_data_sims_amberksz_nzero.npy: $C_{L}^{KK}$ measurements from simulations and data.
  • Used for Figure 2 of the paper.
• ...: Posterior distributions and priors.
  • Used for Figure 3 of the paper.
• sims_data_for_likelihood_with_and_without_systematic_for_plotting.npy: $C_{L}^{KK}$ measurements from simulations for diffenent analysis choices.
  • Used for (Appendix) Figure 4 of the paper.
• ...: Posterior distributions and priors.
  • Used for (Appendix) Figure 5 of the paper.