Electrons Everywhere, All at Once: A Novel kSZ Estimator for Electron-Electron Correlations

Fuente: arXiv
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Autori principali: Kumar, Neha Anil, Çalışkan, Mesut, Hotinli, Selim C., Smith, Kendrick, Kamionkowski, Marc
Natura: Preprint
Pubblicazione: 2025
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author Kumar, Neha Anil
Çalışkan, Mesut
Hotinli, Selim C.
Smith, Kendrick
Kamionkowski, Marc
author_facet Kumar, Neha Anil
Çalışkan, Mesut
Hotinli, Selim C.
Smith, Kendrick
Kamionkowski, Marc
contents Recent advancements in small-scale observations of the cosmic microwave background (CMB) have provided a unique opportunity to characterize the distribution of baryons in the outskirts of galaxies via stacking-based analyses of the kinetic Sunyaev-Zel'dovich (kSZ) effect. Such measurements, mathematically equivalent to probing the galaxy-electron cross-correlation, have revealed that gas is more extended than dark matter and that the strength of baryonic feedback may vary with halo mass and redshift. However, because these analyses are conditioned on galaxy positions, the inferred electron distributions remain biased by uncertain galaxy-halo modeling on small scales. In this work, we present a novel kSZ$\times$galaxy four-point estimator that directly probes the full ionized electron field, extending beyond the gas traced by luminous galaxies. This method exploits large-scale velocity reconstruction from galaxy surveys to characterize the electron distribution unbiased by small-scale galaxy clustering. We forecast that the proposed signal can be measured with a signal-to-noise ratio of $\sim3$ ($\sim13$) for a configuration corresponding to Atacama Cosmology Telescope DR6 (Simons Observatory) CMB data combined with spectroscopic galaxy samples from DESI. This approach will enable the first tomographic measurements of the electron auto-power spectrum, providing new constraints on baryonic feedback and its role in shaping cosmic structure.
format Preprint
id arxiv_https___arxiv_org_abs_2509_18249
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Electrons Everywhere, All at Once: A Novel kSZ Estimator for Electron-Electron Correlations
Kumar, Neha Anil
Çalışkan, Mesut
Hotinli, Selim C.
Smith, Kendrick
Kamionkowski, Marc
Cosmology and Nongalactic Astrophysics
Recent advancements in small-scale observations of the cosmic microwave background (CMB) have provided a unique opportunity to characterize the distribution of baryons in the outskirts of galaxies via stacking-based analyses of the kinetic Sunyaev-Zel'dovich (kSZ) effect. Such measurements, mathematically equivalent to probing the galaxy-electron cross-correlation, have revealed that gas is more extended than dark matter and that the strength of baryonic feedback may vary with halo mass and redshift. However, because these analyses are conditioned on galaxy positions, the inferred electron distributions remain biased by uncertain galaxy-halo modeling on small scales. In this work, we present a novel kSZ$\times$galaxy four-point estimator that directly probes the full ionized electron field, extending beyond the gas traced by luminous galaxies. This method exploits large-scale velocity reconstruction from galaxy surveys to characterize the electron distribution unbiased by small-scale galaxy clustering. We forecast that the proposed signal can be measured with a signal-to-noise ratio of $\sim3$ ($\sim13$) for a configuration corresponding to Atacama Cosmology Telescope DR6 (Simons Observatory) CMB data combined with spectroscopic galaxy samples from DESI. This approach will enable the first tomographic measurements of the electron auto-power spectrum, providing new constraints on baryonic feedback and its role in shaping cosmic structure.
title Electrons Everywhere, All at Once: A Novel kSZ Estimator for Electron-Electron Correlations
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2509.18249