Article

The Atacama Cosmology Telescope: Large-scale velocity reconstruction with the kinematic Sunyaev-Zel'dovich effect and DESI LRGs

Fiona McCarthyCenter for Computational Astrophysics, Flatiron Institute, 162 5th Avenue, New York, NY 10010, U.S.ANicholas BattagliaDepartment of Astronomy, Cornell University, Ithaca, NY 14850, U.S.ARachel BeanDepartment of Astronomy, Cornell University, Ithaca, NY 14850, U.S.AJ. Richard BondCanadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, ON, M5S 3H8, CanadaHongbo CaiDepartment of Astronomy, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, ChinaErminia CalabreseSchool of Physics and Astronomy, Cardiff University, The Parade, Cardiff, Wales CF24 3AA, U.KWilliam R. CoultonDAMTP, Centre for Mathematical Sciences, Wilberforce Road, Cambridge CB3 0WA, U.KMark J. DevlinDepartment of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104, U.S.AJo DunkleyDepartment of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544, U.S.AS. FerraroBerkeley Center for Cosmological Physics, University of California, Berkeley, CA 94720, U.S.AVera GluscevicDepartment of Physics and Astronomy, University of Southern California, Los Angeles, CA 90007, U.S.AYilun GuanDunlap Institute for Astronomy & Astrophysics, University of Toronto, 50 St. George St., Toronto ON M5S 3H4, CanadaJ. Colin HillDepartment of Physics, Columbia University, New York, NY 10027, U.S.AMatthew C. JohnsonDepartment of Physics and Astronomy, York University, Toronto, ON M3J 1P3, CanadaAleksandra KusiakDepartment of Physics, Columbia University, New York, NY 10027, U.S.AAlex LaguëDepartment of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104, U.S.AN. MacCrannDAMTP, Centre for Mathematical Sciences, Wilberforce Road, Cambridge CB3 0WA, U.KMathew S. MadhavacherilDepartment of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104, U.S.AKavilan MoodleyAstrophysics Research Centre, University of KwaZulu-Natal, Westville Campus, Durban 4041, South AfricaSigurd NæssInstitute for theoretical astrophysics, University of Oslo, NorwayFrank J. QuDAMTP, Centre for Mathematical Sciences, Wilberforce Road, Cambridge CB3 0WA, U.KBernardita Ried GuachallaDepartment of Physics, Stanford University, Stanford, CA 94305-4085, U.S.ANeelima SehgalPhysics and Astronomy Department, Stony Brook University, Stony Brook, NY 11794, U.S.ABlake D. SherwinDAMTP, Centre for Mathematical Sciences, Wilberforce Road, Cambridge CB3 0WA, U.KCristobál SifónInstituto de Física, Pontificia Universidad Católica de Valparaíso, Casilla 4059, Valparaíso, ChileKendrick M. SmithPerimeter Institute for Theoretical Physics, 31 Caroline St N, Waterloo, ON N2L 2Y5, CanadaSuzanne T. StaggsJoseph Henry Laboratories of Physics, Jadwin Hall, Princeton University, Princeton, NJ 08544, U.S.AAlexander van EngelenSchool of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, U.S.AEve M. VavagiakisDepartment of Astronomy, Cornell University, Ithaca, NY 14850, U.S.AEdward J. WollackNASA Goddard Space Flight Center, Greenbelt, MD 20771, U.S.A

Journal of Cosmology and Astroparticle Physicsjournal2025en

ABI

Abstract

Abstract The kinematic Sunyaev-Zel'dovich (kSZ) effect induces a non-zero density-density-temperature bispectrum, which we can use to reconstruct the large-scale velocity field from a combination of cosmic microwave background (CMB) and galaxy density measurements, in a procedure known as “kSZ velocity reconstruction”. This method has been forecast to constrain large-scale modes with future galaxy and CMB surveys, improving their measurement beyond what is possible with the galaxy surveys alone. Such measurements will enable tighter constraints on large-scale signals such as primordial non-Gaussianity, deviations from homogeneity, and modified gravity. In this work, we demonstrate a statistically significant measurement of kSZ velocity reconstruction for the first time, by applying quadratic estimators to the combination of the ACT DR6 CMB+kSZ map and the DESI LRG galaxies (with photometric redshifts) in order to reconstruct the velocity field. We do so using a formalism appropriate for the 2-dimensional projected galaxy fields that we use, which naturally incorporates the curved-sky effects important on the largest scales. We find evidence for the signal by cross-correlating with an external estimate of the velocity field from the spectroscopic BOSS survey and rejecting the null (no-kSZ) hypothesis at 3.8σ. Our work presents a first step towards the use of this observable for cosmological analyses.

Topics

Cosmology and Gravitation Theories Galaxies: Formation, Evolution, Phenomena Radio Astronomy Observations and Technology

Identifiers

DOI: 10.1088/1475-7516/2025/05/057

Citations and references

Cited by 0122 references

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