A new constraint on the y-distortion with FIRAS: implications for feedback models in galaxy formation and cosmic shear measurements

2025/12/02 by Fabbian, Giulio, Bianchini, Federico, Sabyr, Alina +4 · 1 citation
#Astrophysics of Galaxies (astro-ph.GA) #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences

paper · doi:10.48550/arxiv.2512.03038

Abstract

The y-type distortion of the blackbody spectrum of the cosmic microwave background radiation probes the pressure of the gas trapped in galaxy groups and clusters. We reanalyze archival data of the FIRAS instrument with an improved astrophysical foreground cleaning technique, and measure a mean y-distortion of ⟨ y⟩ = (1.2± 2.0) × 10^-6 (⟨ y⟩\lesssim 5.2× 10^-6 at 95% C.L.), a factor of ∼ 3 tighter than the original FIRAS results. This measurement directly rules out many models of baryonic feedback as implemented in cosmological hydrodynamical simulations, mostly using information in objects with mass M\lesssim 10¹⁴ \rm M_\odot. We discuss its implications for the analysis of cosmic shear and kinetic Sunyaev-Zel'dovich effect data, and future spectral distortion experiments.

Citations

• ArXiv

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