Looking for a twist: probing the cosmological gravitomagnetic effect via weak lensing-kSZ cross correlations

Barrera-Hinojosa, Cristian; Li, Baojiu; Cai, Yan-Chuan

Abstract

General relativity predicts that the rotational momentum flux of matter twists the space–time via a vector gravitomagnetic (frame-dragging) field, which remains undetected in cosmology. This vector field induces an additional gravitational lensing effect; at the same time, the momentum field sources the kinetic Sunyaev–Zel’dovich (kSZ) effect. The common origin of these two effects allows us to probe the gravitomagnetic signal via their cross-correlations. In this paper, we explore the possibility of detecting the gravitomagnetic field in Λ cold dark matter by cross-correlating the weak-lensing convergence field with the cosmic microwave background (CMB) temperature map, which is imprinted with the kSZ signal. This approach allows us to extract the gravitomagnetic effect because the cross-correlation between the standard Newtonian contribution to the weak-lensing convergence field, κΦ⁠, and the kSZ effect is expected to vanish. We study the cross-correlations with a suite of large-volume Newtonian N-body simulations and a small-volume, high-resolution, general-relativistic counterpart. We show that insufficient simulation resolution can introduce significant spurious correlations between κΦ and kSZ. From the high-resolution simulation, we find that the cumulative signal-to-noise ratio (SNR) of the kSZ-gravitomagnetic convergence field can reach almost 15 (30) at ℓ ≃ 5000 (104) for the lensing source redshift zs = 0.83, if only cosmic variance is considered. We make forecast for next-generation lensing surveys such as EUCLID and LSST, and CMB experiments such as Simons Observatory and CMB-S4, and find that, for zs = 1.4, the cumulative SNR can exceed 5 (9) at ℓ ≃ 5000 (104), indicating that the cosmological gravitomagnetic effect can be detected, if several foreground contaminations can be removed.

Citation

Barrera-Hinojosa, C., Li, B., & Cai, Y. (2022). Looking for a twist: probing the cosmological gravitomagnetic effect via weak lensing-kSZ cross correlations. Monthly Notices of the Royal Astronomical Society, 510(3), 3589-3604. https://doi.org/10.1093/mnras/stab3657

• Journal Article Type: Article
• Acceptance Date: Dec 8, 2021
• Online Publication Date: Dec 20, 2021
• Publication Date: 2022-03
• Deposit Date: Oct 27, 2021
• Publicly Available Date: Jun 14, 2022
• Journal: Monthly Notices of Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 510
• Issue: 3
• Pages: 3589-3604
• DOI: https://doi.org/10.1093/mnras/stab3657
• Public URL: https://durham-repository.worktribe.com/output/1229818
• Related Public URLs: https://arxiv.org/abs/2109.02632