Measuring baryonic feedback with the kinematic Sunyaev-Zel’dovich effect around DESI photometric galaxies

Dec 04, 2023 - 11:00 am to 12:00 pm

Campus, Varian 355

Boryana Hadzhiyska (LBL) In Person

Recent advancements in cosmological observations have provided an unprecedented opportunity to investigate the distribution of baryons relative to the underlying matter. In this work, we pioneer the use of photometric redshifts from the imaging survey of the Dark Energy Spectroscopic Instrument (DESI) to probe the stacked kinematic Sunyaev-Zel'dovich (kSZ) effect with the Atacama Cosmology Telescope (ACT) around DESI luminous red galaxies (LRGs) and infer the distribution of baryons. As the LRG photometric sample is split into 4 bins, we provide an estimate of the signal as a function of redshift. We find a surprising amount of baryonic feedback, which significantly exceeds predictions from state-of-the-art hydrodynamical simulations such as IllustrisTNG. Therefore, of particular relevance to the astrophysical community is the potential to recalibrate large hydrodynamical simulations and bridge the gap between theory and observations. In addition, our finding bears implications for the effect of baryons on the matter power spectrum and can thus help resolve hotly debated disparities between weak lensing surveys and cosmic microwave background (CMB) experiments such as the low S8 tension.