Determine the origin and universality of y–tau scaling-relation differences

Determine whether the variation in the fitted parameters of the empirical Compton-$y$–optical-depth scaling relation among the DESI luminous red galaxy, Bright Galaxy Survey, and eROMaPPer samples is caused by differences in sample properties such as halo mass and redshift or by residual thermal SZ systematic effects.

Background

The paper derives $bar{y}-\bar{\tau}$ scaling relations for three tracer samples and finds that the fitted normalization and slope differ between samples. These parameters depend on sample characteristics and may also be affected by residual contamination from dust, the cosmic infrared background, and radio sources.

The authors explicitly leave unresolved whether the observed variation reflects genuine differences in the halo populations or uncorrected measurement systematics. Resolving this issue is important for assessing whether the scaling relation is universal and transferable across CMB surveys and galaxy samples.