2026-04-17T01:32:38Zhttps://recercat.cat/oai/request

oai:recercat.cat:2117/4423832026-01-22T09:49:24Zcom_2072_1033col_2072_452950

00925njm 22002777a 4500 dc Qu, Frank J. author Hang, Qianjun author Farren, Gerrit author Bolliet, Boris author Aguilar, Jessica Nicole author Ahlen, Steven author Alam, Shadab author Brooks, David author Cai, Yan-Chuan author Calabrese, Erminia author Claybaugh, Todd author de la Macorra, Axel author Devlin, Mark J. author Doel, Peter author Embil Villagra, Carmen author Ferraro, Simone author Pérez Ràfols, Ignasi author 2025-05-15 We measure the growth of cosmic density fluctuations on large scales and across the redshift range 0.3 <¿ <0.8 through galaxy clustering and the cross-correlation of the ACT data release 6 cosmic microwave background (CMB) lensing map and galaxies from the Dark Energy Spectroscopic Instrument Legacy Survey, using three galaxy samples spanning the redshifts of 0.3 ¿¿ ¿0.45, 0.45 ¿¿ ¿0.6, 0.6 ¿¿ ¿0.8. We adopt a scale cut where nonlinear effects are negligible, so that the cosmological constraints are derived from the linear regime. We determine the amplitude of matter fluctuations over all three redshift bins using Atacama Cosmology Telescope (ACT) data alone to be ¿8 =¿8¿(O¿/0.3)0.5 =0.772 ±0.040 in a joint analysis combining the three redshift bins and ACT lensing alone. Using a combination of ACT and Planck data we obtain ¿8 =0.765 ±0.032. The lowest redshift bin used is the least constraining and exhibits a ~2¿¿ tension with the other redshift bins; thus we also report constraints excluding the first redshift bin, giving ¿8 =0.785 ±0.033 for the combination of ACT and Planck. This result is in excellent agreement at the 0.3¿¿ level with measurements from galaxy lensing, but is 1.8¿¿ lower than predictions based on Planck primary CMB data. Understanding whether this hint of discrepancy in the growth of structure at low redshifts arises from a fluctuation, from systematics in data, or from new physics is a high priority for forthcoming CMB lensing and galaxy cross-correlation analyses. Peer Reviewed Postprint (published version) Àrees temàtiques de la UPC::Física Cosmic microwave background Cosmological parameters Cosmology Dark matter Evolution of the Universe Large scale structure of the Universe Atacama Cosmology Telescope DR6 and DESI: Structure growth measurements from the cross-correlation of DESI legacy imaging galaxies and CMB lensing from ACT DR6 and Planck PR4