학술논문
The Atacama Cosmology Telescope: Cosmology from Cross-correlations of unWISE Galaxies and ACT DR6 CMB Lensing
Document Type
article
Author
Gerrit S. Farren; Alex Krolewski; Niall MacCrann; Simone Ferraro; Irene Abril-Cabezas; Rui An; Zachary Atkins; Nicholas Battaglia; J. Richard Bond; Erminia Calabrese; Steve K. Choi; Omar Darwish; Mark J. Devlin; Adriaan J. Duivenvoorden; Jo Dunkley; J. Colin Hill; Matt Hilton; Kevin M. Huffenberger; Joshua Kim; Thibaut Louis; Mathew S. Madhavacheril; Gabriela A. Marques; Jeff McMahon; Kavilan Moodley; Lyman A. Page; Bruce Partridge; Frank J. Qu; Emmanuel Schaan; Neelima Sehgal; Blake D. Sherwin; Cristóbal Sifón; Suzanne T. Staggs; Alexander Van Engelen; Cristian Vargas; Lukas Wenzl; Martin White; Edward J. Wollack
Source
The Astrophysical Journal, Vol 966, Iss 2, p 157 (2024)
Subject
Language
English
ISSN
1538-4357
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 ${S}_{8}\equiv {\sigma }_{8}{({{\rm{\Omega }}}_{m}/0.3)}^{0.5}=0.813\pm 0.021$ 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.