Assess radio-source contamination in pairwise kSZ measurements

Determine how contamination from radio sources affects the pairwise kinematic Sunyaev–Zel’dovich measurements for the DESI DR1 luminous red galaxy, Bright Galaxy Survey, and eROMaPPer samples, in order to establish whether the contamination biases the kSZ-derived optical depths.

Background

The analysis finds that radio sources within the aperture-photometry disks substantially suppress the measured thermal SZ signal, while the pairwise kSZ estimator is expected to be less affected because it uses pairwise differencing. However, the kSZ measurements used for comparison were obtained from the full, radio-contaminated samples, whereas the tSZ measurements were also recomputed after removing radio-contaminated sources.

The unresolved issue is whether radio contamination nevertheless biases the pairwise kSZ signal or its inferred optical depth. Resolving this would be necessary for a consistent comparison between radio-clean tSZ measurements and kSZ-derived optical depths.