A new measurement of the FRB DM-galaxy cross correlation and a first joint analysis with the kinematic SZ effect

Samuel McCarty; Liam Connor; Kritti Sharma; Simone Ferraro; Vikram Ravi; Elisabeth Krause; Boryana Hadzhiyska; Vishnu Balakrishnan; Casey Law; Pranav Sanghavi; Kaitlyn Shin

arXiv · 2608.11296

A new measurement of the FRB DM-galaxy cross correlation and a first joint analysis with the kinematic SZ effect

Samuel McCarty·Liam Connor·Kritti Sharma·Simone Ferraro·Vikram Ravi·Elisabeth Krause·Boryana Hadzhiyska·Vishnu Balakrishnan·Casey Law·Pranav Sanghavi·Kaitlyn Shin

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Abstract

Understanding the distribution of cosmic baryons is crucial for advancing cosmology and galaxy formation. Localized Fast Radio Bursts (FRBs) are a promising new probe of the diffuse gas, but measurements thus far have been limited by small sample size. In this work, we measure the FRB dispersion measure (DM)-galaxy cross correlation with 130 localized FRBs, including new spectroscopic host redshifts from the DSA-110, and the DESI Legacy Survey Bright Galaxy Sample. We detect this signal at the highest significance to date ($6.5\sigma$) in both configuration and harmonic space. By comparing to simulations and a halo model, we demonstrate that this statistic can constrain the strength of baryonic feedback. Our measurements disfavor a no-feedback scenario in which gas traces the underlying dark matter at $\sim\,9\sigma$. In addition to small scale feedback, this represents one of the first direct measurements of the clustering of electrons on scales larger than a few Mpc. We compare our measurement to recent kinematic Sunyaev-Zeldovich effect (kSZ) studies, which show good agreement despite the differences in observational methods and sample selection. Finally, we make a first attempt at breaking the kSZ optical depth degeneracy with FRBs, jointly measuring the growth rate of large-scale structure $f\sigma_8$. With future samples, FRB two-point statistics will provide precision constraints on the distribution of cosmic baryons and complement other probes.

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Samuel McCarty, Liam Connor, Kritti Sharma, Simone Ferraro, Vikram Ravi, Elisabeth Krause, Boryana Hadzhiyska, Vishnu Balakrishnan, Casey Law, Pranav Sanghavi, Kaitlyn Shin. 2026-08-11. A new measurement of the FRB DM-galaxy cross correlation and a first joint analysis with the kinematic SZ effect. https://arxiv.org/abs/2608.11296

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