Farren, Gerrit S., Krolewski, Alex, MacCrann, Niall, Ferraro, Simone, Abril-Cabezas, Irene, An, Rui, Atkins, Zachary, Battaglia, Nicholas, Bond, J. Richard, Calabrese, Erminia ![]() ![]() |
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Abstract
We present tomographic measurements of structure growth using cross-correlations of Atacama Cosmology Telescope (ACT) DR6 and Planck cosmic microwave background (CMB) lensing maps with the unWISE Blue and Green galaxy samples, which span the redshift ranges 0.2 ≲ z ≲ 1.1 and 0.3 ≲ z ≲ 1.8, respectively. We improve on prior unWISE cross-correlations not just by making use of the new, high-precision ACT DR6 lensing maps, but also by including additional spectroscopic data for redshift calibration and by analyzing our measurements with a more flexible theoretical model. We determine the amplitude of matter fluctuations at low redshifts (z ≃ 0.2–1.6), finding S8≡σ8(Ωm/0.3)0.5=0.813±0.021 using the ACT cross-correlation alone and S 8 = 0.810 ± 0.015 with a combination of Planck and ACT cross-correlations; these measurements are fully consistent with the predictions from primary CMB measurements assuming standard structure growth. The addition of baryon acoustic oscillation data breaks the degeneracy between σ 8 and Ω m , allowing us to measure σ 8 = 0.813 ± 0.020 from the cross-correlation of unWISE with ACT and σ 8 = 0.813 ± 0.015 from the combination of cross-correlations with ACT and Planck. These results also agree with the expectations from primary CMB extrapolations in ΛCDM cosmology; the consistency of σ 8 derived from our two redshift samples at z ∼ 0.6 and 1.1 provides a further check of our cosmological model. Our results suggest that structure formation on linear scales is well described by ΛCDM even down to low redshifts z ≲ 1.
Item Type: | Article |
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Date Type: | Published Online |
Status: | Published |
Schools: | Advanced Research Computing @ Cardiff (ARCCA) Physics and Astronomy |
Additional Information: | License information from Publisher: LICENSE 1: URL: http://creativecommons.org/licenses/by/4.0/, Type: cc-by |
Publisher: | American Astronomical Society |
ISSN: | 0004-637X |
Date of First Compliant Deposit: | 3 May 2024 |
Date of Acceptance: | 6 March 2024 |
Last Modified: | 11 Jun 2024 12:31 |
URI: | https://orca.cardiff.ac.uk/id/eprint/168689 |
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