Dark Energy Survey Year 6 results: Redshift calibration of the MagLim++ lens sample

Giannini, G. [Institute of Space Sciences (ICE; CSIC); University of Chicago] (ORCID:0000000237301750); Alarcon, A. [Institute of Space Sciences (ICE; CSIC)]; d’Assignies, W. [The Barcelona Institute of Science and Technology]; Bernstein, G. M. [University of Pennsylvania]; Troxel, M. A. [Duke University]; Chang, C. [University of Chicago; University of Chicago]; Yin, B. [Duke University]; Amon, A. [Princeton University]; Myles, J. [Princeton University]; Weaverdyck, N. [University of California; Lawrence Berkeley National Laboratory]; Porredon, A. [Ruhr University Bochum; Centro de Investigaciones Energéticas]; Anbajagane, D. [University of Chicago]; Avila, S. [Centro de Investigaciones Energéticas]; Bechtol, K. [University of Wisconsin-Madison]; Becker, M. R. [Argonne National Laboratory]; Blazek, J. [Northeastern University]; Crocce, M. [Institut d’Estudis Espacials de Catalunya (IEEC); Institute of Space Sciences (ICE; CSIC)]; Gruen, D. [University Observatory]; Rodriguez-Monroy, M. [Universidad Autónoma de Madrid; CNRS Université Paris-Saclay]; Sánchez, C. [The Barcelona Institute of Science and Technology; Universitat Autònoma de Barcelona (UAB)]; Sevilla-Noarbe, I. [Centro de Investigaciones Energéticas]; Aguena, M. [INAF-Osservatorio Astronomico di Trieste; Laboratório Interinstitucional de e-Astronomia—LIneA]; Allam, S. [Fermi National Accelerator Laboratory]; Alves, O. [University of Michigan]; Andrade-Oliveira, F. [University of Zürich]; Bacon, D. [University of Portsmouth]; Bocquet, S. [University Observatory]; Brooks, D. [University College London]; Camilleri, R. [University of Queensland]; Carnero Rosell, A. [Universidad de La Laguna; Laboratório Interinstitucional de e-Astronomia—LIneA; Instituto de Astrofisica de Canarias]; Carretero, J. [The Barcelona Institute of Science and Technology]; Cawthon, R. [Oxford College of Emory University]; da Costa, L. N. [Laboratório Interinstitucional de e-Astronomia—LIneA]; da Silva Pereira, M. E. [Universität Hamburg]; Davis, T. M. [University of Queensland]; De Vicente, J. [Centro de Investigaciones Energéticas]; DePoy, D. L. [Texas A&M University]; Desai, S. [IIT Hyderabad]; Diehl, H. T. [Fermi National Accelerator Laboratory]; Dodelson, S. [Fermi National Accelerator Laboratory; University of Chicago; University of Chicago]; Doel, P. [University College London]; Doux, C. [University of Pennsylvania; Université Grenoble Alpes]; Drlica-Wagner, A. [University of Chicago; Fermi National Accelerator Laboratory; University of Chicago]; Elvin-Poole, J. [University of Waterloo]; Everett, S. [California Institute of Technology]; Evrard, A. E. [University of Michigan; University of Michigan]; Flaugher, B. [Fermi National Accelerator Laboratory]; Frieman, J. [University of Chicago; Fermi National Accelerator Laboratory; University of Chicago]; García-Bellido, J. [Universidad Autonoma de Madrid]; Gatti, M. [University of Chicago; Institute of Space Sciences (ICE; CSIC)]; Gaztanaga, E. [University of Portsmouth; Institute of Space Sciences (ICE; CSIC); Institut d’Estudis Espacials de Catalunya (IEEC)]; Giles, P. [University of Sussex]; Gruendl, R. A. [University of Illinois at Urbana-Champaign; Center for Astrophysical Surveys]; Gutierrez, G. [Fermi National Accelerator Laboratory]; Herner, K. [Fermi National Accelerator Laboratory]; Hinton, S. R. [University of Queensland]; Hollowood, D. L. [Santa Cruz Institute for Particle Physics]; Honscheid, K. [The Ohio State University; The Ohio State University]; Huterer, D. [University of Michigan]; James, D. J. [Center for Astrophysics | Harvard & Smithsonian]; Kuehn, K. [Macquarie University; Lowell Observatory]; Lahav, O. [University College London]; Lee, S. [California Institute of Technology; Ohio University]; Lin, H. [Fermi National Accelerator Laboratory]; Marshall, J. L. [Texas A&M University]; Mena-Fernández, J. [Université Grenoble Alpes; Aix Marseille University]; Menanteau, F. [Center for Astrophysical Surveys; University of Illinois at Urbana-Champaign]; Miquel, R. [The Barcelona Institute of Science and Technology; Institució Catalana de Recerca i Estudis Avançats]; Muir, J. [Perimeter Institute for Theoretical Physics; University of Cincinnati]; Ogando, R. L. C. [Observatório Nacional]; Petravick, D. [Center for Astrophysical Surveys]; Plazas Malagón, A. A. [Stanford University; SLAC National Accelerator Laboratory]; Prat, J. [KTH Royal Institute of Technology and Stockholm University; University of Copenhagen]; Raveri, M. [University of Genova and INFN]; Rykoff, E. S. [SLAC National Accelerator Laboratory; Stanford University]; Samuroff, S. [The Barcelona Institute of Science and Technology; Northeastern University]; Sanchez, E. [Centro de Investigaciones Energéticas]; Sanchez Cid, D. [University of Zürich; Centro de Investigaciones Energéticas]; Shin, T. [Stony Brook University]; Smith, M. [Lancaster University]; Suchyta, E. [Oak Ridge National Laboratory]; Swanson, M. E. C. [Center for Astrophysical Surveys]; Tarle, G. [University of Michigan]; Thomas, D. [University of Portsmouth]; To, C. [University of Chicago]; Tucker, D. L. [Fermi National Accelerator Laboratory]; Vikram, V. [Central University of Kerala]; Yamamoto, M. [Duke University; Princeton University]

doi:10.1103/mkwr-bfls

DOE OSTI · 3647891

Dark Energy Survey Year 6 results: Redshift calibration of the MagLim++ lens sample

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Abstract

In this work, we derive and calibrate the redshift distribution of the MagLim++ lens galaxy sample used in the Dark Energy Survey Year 6 (DES Y6) 3 x 2pt cosmology analysis. The 3 x 2pt analysis combines galaxy clustering from the lens galaxy sample and weak gravitational lensing. The redshift distributions are inferred using the SOMPZ method - a Self-Organizing Map framework that combines deep-field multi-band photometry, wide-field data, and a synthetic source injection ( B alrog) catalog. Key improvements over the DES Year 3 (Y3) calibration include a noise-weighted SOM metric, an expanded Balrog catalogue, and an improved scheme for propagating systematic uncertainties, which allows us to generate O(10 8 ) redshift realizations that collectively span the dominant sources of uncertainty. These realizations are then combined with independent clustering-redshift measurements via importance sampling. The resulting calibration achieves typical uncertainties on the mean redshift of 1-2%, corresponding to a 20-30% average reduction relative to DES Y3. We compress the n(z) uncertainties into a small number of orthogonal modes for use in cosmological inference. Marginalizing over these modes leads to only a minor degradation in cosmological constraints. Here, this analysis establishes the MagLim++ sample as a robust lens sample for precision cosmology with DES Y6 and provides a scalable framework for future surveys.

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Giannini, G. [Institute of Space Sciences (ICE; CSIC); University of Chicago] (ORCID:0000000237301750), Alarcon, A. [Institute of Space Sciences (ICE; CSIC)], d’Assignies, W. [The Barcelona Institute of Science and Technology], Bernstein, G. M. [University of Pennsylvania], Troxel, M. A. [Duke University], Chang, C. [University of Chicago; University of Chicago], Yin, B. [Duke University], Amon, A. [Princeton University], Myles, J. [Princeton University], Weaverdyck, N. [University of California; Lawrence Berkeley National Laboratory], Porredon, A. [Ruhr University Bochum; Centro de Investigaciones Energéticas], Anbajagane, D. [University of Chicago], Avila, S. [Centro de Investigaciones Energéticas], Bechtol, K. [University of Wisconsin-Madison], Becker, M. R. [Argonne National Laboratory], Blazek, J. [Northeastern University], Crocce, M. [Institut d’Estudis Espacials de Catalunya (IEEC); Institute of Space Sciences (ICE; CSIC)], Gruen, D. [University Observatory], Rodriguez-Monroy, M. [Universidad Autónoma de Madrid; CNRS Université Paris-Saclay], Sánchez, C. [The Barcelona Institute of Science and Technology; Universitat Autònoma de Barcelona (UAB)], Sevilla-Noarbe, I. [Centro de Investigaciones Energéticas], Aguena, M. [INAF-Osservatorio Astronomico di Trieste; Laboratório Interinstitucional de e-Astronomia—LIneA], Allam, S. [Fermi National Accelerator Laboratory], Alves, O. [University of Michigan], Andrade-Oliveira, F. [University of Zürich], Bacon, D. [University of Portsmouth], Bocquet, S. [University Observatory], Brooks, D. [University College London], Camilleri, R. [University of Queensland], Carnero Rosell, A. [Universidad de La Laguna; Laboratório Interinstitucional de e-Astronomia—LIneA; Instituto de Astrofisica de Canarias], Carretero, J. [The Barcelona Institute of Science and Technology], Cawthon, R. [Oxford College of Emory University], da Costa, L. N. [Laboratório Interinstitucional de e-Astronomia—LIneA], da Silva Pereira, M. E. [Universität Hamburg], Davis, T. M. [University of Queensland], De Vicente, J. [Centro de Investigaciones Energéticas], DePoy, D. L. [Texas A&M University], Desai, S. [IIT Hyderabad], Diehl, H. T. [Fermi National Accelerator Laboratory], Dodelson, S. [Fermi National Accelerator Laboratory; University of Chicago; University of Chicago], Doel, P. [University College London], Doux, C. [University of Pennsylvania; Université Grenoble Alpes], Drlica-Wagner, A. [University of Chicago; Fermi National Accelerator Laboratory; University of Chicago], Elvin-Poole, J. [University of Waterloo], Everett, S. [California Institute of Technology], Evrard, A. E. [University of Michigan; University of Michigan], Flaugher, B. [Fermi National Accelerator Laboratory], Frieman, J. [University of Chicago; Fermi National Accelerator Laboratory; University of Chicago], García-Bellido, J. [Universidad Autonoma de Madrid], Gatti, M. [University of Chicago; Institute of Space Sciences (ICE; CSIC)], Gaztanaga, E. [University of Portsmouth; Institute of Space Sciences (ICE; CSIC); Institut d’Estudis Espacials de Catalunya (IEEC)], Giles, P. [University of Sussex], Gruendl, R. A. [University of Illinois at Urbana-Champaign; Center for Astrophysical Surveys], Gutierrez, G. [Fermi National Accelerator Laboratory], Herner, K. [Fermi National Accelerator Laboratory], Hinton, S. R. [University of Queensland], Hollowood, D. L. [Santa Cruz Institute for Particle Physics], Honscheid, K. [The Ohio State University; The Ohio State University], Huterer, D. [University of Michigan], James, D. J. [Center for Astrophysics | Harvard & Smithsonian], Kuehn, K. [Macquarie University; Lowell Observatory], Lahav, O. [University College London], Lee, S. [California Institute of Technology; Ohio University], Lin, H. [Fermi National Accelerator Laboratory], Marshall, J. L. [Texas A&M University], Mena-Fernández, J. [Université Grenoble Alpes; Aix Marseille University], Menanteau, F. [Center for Astrophysical Surveys; University of Illinois at Urbana-Champaign], Miquel, R. [The Barcelona Institute of Science and Technology; Institució Catalana de Recerca i Estudis Avançats], Muir, J. [Perimeter Institute for Theoretical Physics; University of Cincinnati], Ogando, R. L. C. [Observatório Nacional], Petravick, D. [Center for Astrophysical Surveys], Plazas Malagón, A. A. [Stanford University; SLAC National Accelerator Laboratory], Prat, J. [KTH Royal Institute of Technology and Stockholm University; University of Copenhagen], Raveri, M. [University of Genova and INFN], Rykoff, E. S. [SLAC National Accelerator Laboratory; Stanford University], Samuroff, S. [The Barcelona Institute of Science and Technology; Northeastern University], Sanchez, E. [Centro de Investigaciones Energéticas], Sanchez Cid, D. [University of Zürich; Centro de Investigaciones Energéticas], Shin, T. [Stony Brook University], Smith, M. [Lancaster University], Suchyta, E. [Oak Ridge National Laboratory], Swanson, M. E. C. [Center for Astrophysical Surveys], Tarle, G. [University of Michigan], Thomas, D. [University of Portsmouth], To, C. [University of Chicago], Tucker, D. L. [Fermi National Accelerator Laboratory], Vikram, V. [Central University of Kerala], Yamamoto, M. [Duke University; Princeton University]. 2026-07-07. Dark Energy Survey Year 6 results: Redshift calibration of the MagLim++ lens sample. https://doi.org/10.1103/mkwr-bfls

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