The Atacama Cosmology Telescope DR6 and DESI: structure formation over cosmic time with a measurement of the cross-correlation of CMB lensing and luminous red galaxies

Journal Article · 09 December 2024 · Journal of Cosmology and Astroparticle Physics

DOI: https://doi.org/10.1088/1475-7516/2024/12/022 · OSTI ID:3007340

Kim, Joshua ; Sailer, Noah ; Madhavacheril, Mathew S.; Ferraro, Simone ; Abril-Cabezas, Irene ; Aguilar, Jessica Nicole; Ahlen, Steven ; Richard Bond, J.; Brooks, David; Burtin, Etienne; Calabrese, Erminia; Chen, Shi-Fan; Choi, Steve K. ; Claybaugh, Todd; Darwish, Omar; de la Macorra, Axel ; DeRose, Joseph; Devlin, Mark ; Dey, Arjun ; Doel, Peter ; Dunkley, Jo ; Embil-Villagra, Carmen ; Farren, Gerrit S.; Font-Ribera, Andreu ; Forero-Romero, Jaime E. ; Gaztañaga, Enrique; Gluscevic, Vera ; Gontcho, Satya Gontcho A. ; Guy, Julien ; Honscheid, Klaus; Howlett, Cullan ; Kirkby, David ; Kisner, Theodore ; Kremin, Anthony ; Landriau, Martin ; Guillou, Laurent Le ; Levi, Michael E. ; MacCrann, Niall ; Manera, Marc ; Marques, Gabriela A. ; Meisner, Aaron ; Miquel, Ramon; Moodley, Kavilan ; Moustakas, John ; Newburgh, Laura B.; Newman, Jeffrey A. ; Niz, Gustavo ; Orlowski-Scherer, John ; Palanque-Delabrouille, Nathalie ; Percival, Will J. ; Prada, Francisco ; Qu, Frank J. ; Rossi, Graziano; Sanchez, Eusebio ; Schaan, Emmanuel; Schlafly, Edward F. ; Schlegel, David; Schubnell, Michael; Sehgal, Neelima ; Seo, Hee-Jung ; Shaikh, Shabbir ; Sherwin, Blake D.; Sifón, Cristóbal ; Sprayberry, David; Staggs, Suzanne T. ; Tarlé, Gregory ; van Engelen, Alexander ; Weaver, Benjamin Alan; Wenzl, Lukas; White, Martin; Wollack, Edward J. ; Yèche, Christophe ; Zou, Hu

We present a high-significance cross-correlation of CMB lensing maps from the Atacama Cosmology Telescope (ACT) Data Release 6 (DR6) with luminous red galaxies (LRGs) from the Dark Energy Spectroscopic Instrument (DESI) Legacy Survey spectroscopically calibrated by DESI. We detect this cross-correlation at a significance of 38σ; combining our measurement with the Planck Public Release 4 (PR4) lensing map, we detect the cross-correlation at 50σ. Fitting this jointly with the galaxy auto-correlation power spectrum to break the galaxy bias degeneracy with σ₈, we perform a tomographic analysis in four LRG redshift bins spanning 0.4 ≤ z ≤ 1.0 to constrain the amplitude of matter density fluctuations through the parameter combination S₈^× = σ₈ (Ω_m / 0.3)^0.4. Prior to unblinding, we confirm with extragalactic simulations that foreground biases are negligible and carry out a comprehensive suite of null and consistency tests. Using a hybrid effective field theory (HEFT) model that allows scales as small as k_max = 0.6 h/ Mpc, we obtain a 3.3% constraint on S₈^× = σ₈ (Ω_m / 0.3)^0.4 = 0.792^+0.024_-0.028 from ACT data, as well as constraints on S₈^×(z) that probe structure formation over cosmic time. Our result is consistent with the early-universe extrapolation from primary CMB anisotropies measured by Planck PR4 within 1.2σ. Jointly fitting ACT and Planck lensing cross-correlations we obtain a 2.7% constraint of S₈^× = 0.776^+0.019_-0.021, which is consistent with the Planck early-universe extrapolation within 2.1σ, with the lowest redshift bin showing the largest difference in mean. The latter may motivate further CMB lensing tomography analyses at z < 0.6 to assess the impact of potential systematics or the consistency of the ΛCDM model over cosmic time.

• Research Organization: University of Michigan, Ann Arbor, MI (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP); National Science Foundation (NSF)
• Contributing Organization: DESI Collaboration
• Grant/Contract Number: SC0019193; SC0014664; AC02-05CH11231; AC02-07CH11359
• OSTI ID: 3007340
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 12 Vol. 2024; ISSN 1475-7516
• Publisher: IOP PublishingCopyright Statement
• Country of Publication: United States
• Language: English