Shear-kSZ: A New Estimator for the Matter-Electron Power Spectrum from kSZ Tomography and Weak Lensing
Abstract
We propose a new estimator of the electron--matter power spectrum, Pme(k), which correlates the kinematic Sunyaev--Zel'dovich (kSZ) temperature with the product of the line-of-sight velocity field and the weak-lensing convergence. Like the stacked kSZ estimator, it factorizes into a calibratable velocity kernel times Pme(k), but it probes the full matter distribution rather than the gas around a biased tracer. It therefore measures the baryonic suppression of the matter power spectrum, S(k), one of the dominant astrophysical systematics for Stage-IV cosmic shear. We derive an analytic expression for the estimator, validate it against simulations at the per-cent level, and show that its parity structure cancels cosmic microwave background (CMB) foregrounds. We forecast the detectability with a realistic pipeline: velocities reconstructed from the simulated tracers, with and without photometric-redshift errors; the kSZ signal of all the ionized gas along the line of sight; a CMB map with Simons Observatory (SO) noise; and LSST source samples free of intrinsic alignments. A DESI-like spectroscopic sample at 0.5<z<1 over the 20% of the sky that DESI, LSST and SO share gives a $4−−7σ$ detection. Photometric redshifts cost only $5−−10\%$ of the significance, so LSST can supply its own velocity tracers over its full overlap with SO: with tracers at 0.1<z<1.3 and five source samples we find 10σ in an end-to-end simulation, and 13σ with Advanced SO (16σ if extending to z < 1.5). This corresponds to a few-per-cent measurement of S(k) at k≃1--4 h Mpc−1, the scales that matter most for cosmic shear.
Related
- The suppression of the matter power spectrum: strong feedback from X-ray gas mass fractions, kSZ effect profiles, and galaxy–galaxy lensing
- SPT-3G D1: Quadratic-Estimator CMB Lensing Reconstruction and Cosmology
- A Robust Estimator for the Lyman-α Forest 1D Power Spectrum at High Redshift
- Strong Lensing Tomography: Double and pseudo multi-source plane strong gravitational lensing to constrain dark energy
- Strong-lensing perturber signatures in self-interacting dark matter simulations
BibTeX
@misc{hadzhiyska2026shearksz,
title = {{Shear-kSZ: A New Estimator for the Matter-Electron Power Spectrum from kSZ Tomography and Weak Lensing}},
author = {Boryana Hadzhiyska},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2607.27149},
eprint = {2607.27149},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.27149},
}
RIS
TY - UNPB
TI - Shear-kSZ: A New Estimator for the Matter-Electron Power Spectrum from kSZ Tomography and Weak Lensing
AU - Boryana Hadzhiyska
PY - 2026
DA - 2026/10/13
PB - arXiv
DO - 10.48550/arxiv.2607.27149
UR - https://arxiv.org/abs/2607.27149
AB - We propose a new estimator of the electron--matter power spectrum, P_me(k), which correlates the kinematic Sunyaev--Zel'dovich (kSZ) temperature with the product of the line-of-sight velocity field and the weak-lensing convergence. Like the stacked kSZ estimator, it factorizes into a calibratable velocity kernel times P_me(k), but it probes the full matter distribution rather than the gas around a biased tracer. It therefore measures the baryonic suppression of the matter power spectrum, S(k), one of the dominant astrophysical systematics for Stage-IV cosmic shear. We derive an analytic expression for the estimator, validate it against simulations at the per-cent level, and show that its parity structure cancels cosmic microwave background (CMB) foregrounds. We forecast the detectability with a realistic pipeline: velocities reconstructed from the simulated tracers, with and without photometric-redshift errors; the kSZ signal of all the ionized gas along the line of sight; a CMB map with Simons Observatory (SO) noise; and LSST source samples free of intrinsic alignments. A DESI-like spectroscopic sample at 0.5<z<1 over the 20% of the sky that DESI, LSST and SO share gives a $4−−7σ$ detection. Photometric redshifts cost only $5−−10\%$ of the significance, so LSST can supply its own velocity tracers over its full overlap with SO: with tracers at 0.1<z<1.3 and five source samples we find 10σ in an end-to-end simulation, and 13σ with Advanced SO (16σ if extending to z < 1.5). This corresponds to a few-per-cent measurement of S(k) at k≃1--4 h Mpc^−1, the scales that matter most for cosmic shear.
ER -