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Velocity Reconstruction from KSZ: Measuring f_(NL) with ACT and DESILS

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arxiv 2506.21657 v1 pith:YEBPPUJN submitted 2025-06-26 astro-ph.CO

Velocity Reconstruction from KSZ: Measuring f_(NL) with ACT and DESILS

classification astro-ph.CO
keywords desilsgalaxyreconstructionvelocitycorrelationdatafieldfind
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved
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The kinetic Sunyaev-Zel'dovich (kSZ) effect offers an indirect way to reconstruct large-scale cosmic velocities, by correlating high-resolution CMB temperature maps with galaxy surveys. In this work, we present the first three-dimensional reconstruction of the large-scale velocity field using a photometric galaxy survey, using data from the DESI Legacy Imaging Surveys (DESILS) and the Atacama Cosmology Telescope (ACT) DR5. We detect an $11.7\sigma$ correlation between our velocity reconstruction and the galaxy field, using only DESILS LRGs in the northern Galactic hemisphere. We find that the overall amplitude of the kSZ-induced correlation is low relative to a halo model prediction ($b_v = 0.45^{+0.06}_{-0.05}$), in agreement with previous results which find high feedback and smoothed gas profiles near massive galaxies. We use this measurement to place new constraints on local-type primordial non-Gaussianity (PNG), obtaining $f_{\rm NL}\!=\!-39^{+40}_{-33}$. This represents the most stringent $f_{\rm NL}$ constraint from kSZ velocity-based analyses to date. We validate our findings through extensive null tests, including tests for CMB foregrounds based on comparing 90 and 150 GHz CMB data.

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Cited by 11 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. First detection of the moving lens effect with ACT and DESI LS

    astro-ph.CO 2026-05 unverdicted novelty 8.0

    First observational detection of the moving lens effect via cross-correlation of ACT CMB temperature with DESI galaxies, yielding amplitude b_ML = 1.24 ± 0.26 at 4.8σ consistent with halo-model prediction.

  2. Shear-kSZ: A New Estimator for the Matter-Electron Power Spectrum from kSZ Tomography and Weak Lensing

    astro-ph.CO 2026-07 conditional novelty 7.0

    Shear–kSZ correlates kSZ, tomographic line-of-sight velocity, and lensing convergence to measure P_me(k) and thereby the baryonic matter-power suppression S(k) at high forecast significance.

  3. Optimal and exact wide-angle power spectrum estimation

    astro-ph.CO 2026-07 accept novelty 7.0

    For finite-rank signals the optimal wide-angle estimator is the two-ℓ Yamamoto form, whose exact window is a finite FFT-computable sum that improves ultra-large-scale SNR by O(1).

  4. Measurement of the galaxy-velocity power spectrum of DESI tracers with the kinematic Sunyaev-Zeldovich effect using DESI DR2 and ACT DR6

    astro-ph.CO 2026-04 unverdicted novelty 7.0

    DESI DR2 and ACT DR6 data yield 17σ LRG-velocity, 8.3σ ELG-velocity, and 6.8σ QSO-velocity detections plus a 3.1σ velocity-velocity signal, producing f_NL^loc = 15.9_{-34.4}^{+34.6} from the velocity field.

  5. Direct shear $\times$ kSZ correlation: controlling baryons without modeling galaxies

    astro-ph.CO 2026-07 conditional novelty 6.0

    A shear×velocity kSZ template cross-correlated with the CMB is forecast to measure the electron–matter power spectrum to few-percent (ACT/SO) or sub-percent (CMB-HD) precision.

  6. Constraints on the remote quadrupole field from the polarized Sunyaev Zel'dovich effect

    astro-ph.CO 2026-07 conditional novelty 6.0

    A first pSZ bispectrum search with Planck/ACT and unWISE/CIB data finds no signal, giving b_q=1.02±2.64 and τ_rei=−0.01±0.14.

  7. Backlighting the Cosmic Web with Fast Radio Bursts: An Anthology of Dispersion Measure Cross-Correlations with Large-Scale Structure and Baryon Tracers

    astro-ph.CO 2026-04 unverdicted novelty 6.0

    FRB DMs correlate at 2.6-5 sigma with galaxies, weak lensing, CIB, CMB lensing, tSZ, X-ray clusters, SXRB and radio continuum, consistent with moderate feedback models while ruling out weak feedback at 3.5 sigma via SXRB-DM.

  8. Precision Kinematic Sunyaev--Zel'dovich Measurements Across Halo Mass and Redshift with DESI DR2 and ACT DR6: Part I. Luminous Red Galaxies

    astro-ph.CO 2026-04 unverdicted novelty 6.0

    High-significance kSZ measurements around LRGs show gas is redistributed beyond gravitational collapse and imply more efficient feedback in group-scale halos than in standard hydrodynamical models.

  9. Euclid preparation: Testing multi-field inflation with galaxy power spectrum and bispectrum

    astro-ph.CO 2026-05 conditional novelty 5.0

    Validates redshift-space power spectrum and bispectrum analysis on Abacus-PNG mocks to recover unbiased f_NL constraints for Euclid spectroscopic sample.

  10. Probing Dark Energy Microphysics with kSZ Tomography

    astro-ph.CO 2025-11 conditional novelty 5.0

    Fisher-matrix forecasts for LSST- and CMB-S4-like surveys show kSZ tomography tightens constraints on dark energy parameters w0 and wa by 15% and 32% while assessing detectability of perturbations for different sound speeds.

  11. New constraints on primordial non-Gaussianity from large-scale cross-correlations of CMB lensing and the cosmic infrared background

    astro-ph.CO 2026-05 unverdicted novelty 4.0

    Dust-cleaned CIB and CMB lensing cross-correlations yield f_NL^local = 43 ± 23, tightening constraints on local primordial non-Gaussianity.