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Dark Energy Survey Year 6 Results: Redshift Calibration of the MagLim++ Lens Sample

Fuente: arXiv

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Main Authors:	Giannini, G., Alarcon, A., d'Assignies, W., Bernstein, G. M., Troxel, M. A., Chang, C., Yin, B., Amon, A., Myles, J., Weaverdyck, N., Porredon, A., Anbajagane, D., Avila, S., Bechtol, K., Becker, M. R., Blazek, J., Crocce, M., Gruen, D., Rodriguez-Monroy, M., Sánchez, C., Cid, D. Sanchez, Sevilla-Noarbe, I., Aguena, M., Allam, S., Alves, O., Andrade-Oliveira, F., Bacon, D., Bocquet, S., Brooks, D., Camilleri, R., Rosell, A. Carnero, Carretero, J., Cawthon, R., da Costa, L. N., Pereira, M. E. da Silva, Davis, T. M., De Vicente, J., DePoy, D. L., Desai, S., Diehl, H. T., Dodelson, S., Doel, P., Doux, C., Drlica-Wagner, A., Elvin-Poole, J., Everett, S., Evrard, A. E., Flaugher, B., Frieman, J., García-Bellido, J., Gatti, M., Gaztanaga, E., Giles, P., Gruendl, R. A., Gutierrez, G., Herner, K., Hinton, S. R., Hollowood, D. L., Honscheid, K., Huterer, D., James, D. J., Kuehn, K., Lahav, O., Lee, S., Lin, H., Marshall, J. L., Mena-Fernández, J., Menanteau, F., Miquel, R., Muir, J., Ogando, R. L. C., Petravick, D., Malagón, A. A. Plazas, Prat, J., Raveri, M., Rykoff, E. S., Samuroff, S., Sanchez, E., Shin, T., Smith, M., Suchyta, E., Swanson, M. E. C., Tarle, G., Thomas, D., To, C., Tucker, D. L., Vikram, V., Yamamoto, M.
Format:	Preprint
Published:	2025
Subjects:	Cosmology and Nongalactic Astrophysics
Online Access:	Acceder al recurso
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author	Giannini, G. Alarcon, A. d'Assignies, W. Bernstein, G. M. Troxel, M. A. Chang, C. Yin, B. Amon, A. Myles, J. Weaverdyck, N. Porredon, A. Anbajagane, D. Avila, S. Bechtol, K. Becker, M. R. Blazek, J. Crocce, M. Gruen, D. Rodriguez-Monroy, M. Sánchez, C. Cid, D. Sanchez Sevilla-Noarbe, I. Aguena, M. Allam, S. Alves, O. Andrade-Oliveira, F. Bacon, D. Bocquet, S. Brooks, D. Camilleri, R. Rosell, A. Carnero Carretero, J. Cawthon, R. da Costa, L. N. Pereira, M. E. da Silva Davis, T. M. De Vicente, J. DePoy, D. L. Desai, S. Diehl, H. T. Dodelson, S. Doel, P. Doux, C. Drlica-Wagner, A. Elvin-Poole, J. Everett, S. Evrard, A. E. Flaugher, B. Frieman, J. García-Bellido, J. Gatti, M. Gaztanaga, E. Giles, P. Gruendl, R. A. Gutierrez, G. Herner, K. Hinton, S. R. Hollowood, D. L. Honscheid, K. Huterer, D. James, D. J. Kuehn, K. Lahav, O. Lee, S. Lin, H. Marshall, J. L. Mena-Fernández, J. Menanteau, F. Miquel, R. Muir, J. Ogando, R. L. C. Petravick, D. Malagón, A. A. Plazas Prat, J. Raveri, M. Rykoff, E. S. Samuroff, S. Sanchez, E. Shin, T. Smith, M. Suchyta, E. Swanson, M. E. C. Tarle, G. Thomas, D. To, C. Tucker, D. L. Vikram, V. Yamamoto, M.
author_facet	Giannini, G. Alarcon, A. d'Assignies, W. Bernstein, G. M. Troxel, M. A. Chang, C. Yin, B. Amon, A. Myles, J. Weaverdyck, N. Porredon, A. Anbajagane, D. Avila, S. Bechtol, K. Becker, M. R. Blazek, J. Crocce, M. Gruen, D. Rodriguez-Monroy, M. Sánchez, C. Cid, D. Sanchez Sevilla-Noarbe, I. Aguena, M. Allam, S. Alves, O. Andrade-Oliveira, F. Bacon, D. Bocquet, S. Brooks, D. Camilleri, R. Rosell, A. Carnero Carretero, J. Cawthon, R. da Costa, L. N. Pereira, M. E. da Silva Davis, T. M. De Vicente, J. DePoy, D. L. Desai, S. Diehl, H. T. Dodelson, S. Doel, P. Doux, C. Drlica-Wagner, A. Elvin-Poole, J. Everett, S. Evrard, A. E. Flaugher, B. Frieman, J. García-Bellido, J. Gatti, M. Gaztanaga, E. Giles, P. Gruendl, R. A. Gutierrez, G. Herner, K. Hinton, S. R. Hollowood, D. L. Honscheid, K. Huterer, D. James, D. J. Kuehn, K. Lahav, O. Lee, S. Lin, H. Marshall, J. L. Mena-Fernández, J. Menanteau, F. Miquel, R. Muir, J. Ogando, R. L. C. Petravick, D. Malagón, A. A. Plazas Prat, J. Raveri, M. Rykoff, E. S. Samuroff, S. Sanchez, E. Shin, T. Smith, M. Suchyta, E. Swanson, M. E. C. Tarle, G. Thomas, D. To, C. Tucker, D. L. Vikram, V. Yamamoto, M.
contents	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) 3x2pt cosmology analysis. The 3x2pt 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 (Balrog) 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. 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.
format	Preprint
id	arxiv_https___arxiv_org_abs_2509_07964
institution	arXiv
publishDate	2025
record_format	arxiv
spellingShingle	Dark Energy Survey Year 6 Results: Redshift Calibration of the MagLim++ Lens Sample Giannini, G. Alarcon, A. d'Assignies, W. Bernstein, G. M. Troxel, M. A. Chang, C. Yin, B. Amon, A. Myles, J. Weaverdyck, N. Porredon, A. Anbajagane, D. Avila, S. Bechtol, K. Becker, M. R. Blazek, J. Crocce, M. Gruen, D. Rodriguez-Monroy, M. Sánchez, C. Cid, D. Sanchez Sevilla-Noarbe, I. Aguena, M. Allam, S. Alves, O. Andrade-Oliveira, F. Bacon, D. Bocquet, S. Brooks, D. Camilleri, R. Rosell, A. Carnero Carretero, J. Cawthon, R. da Costa, L. N. Pereira, M. E. da Silva Davis, T. M. De Vicente, J. DePoy, D. L. Desai, S. Diehl, H. T. Dodelson, S. Doel, P. Doux, C. Drlica-Wagner, A. Elvin-Poole, J. Everett, S. Evrard, A. E. Flaugher, B. Frieman, J. García-Bellido, J. Gatti, M. Gaztanaga, E. Giles, P. Gruendl, R. A. Gutierrez, G. Herner, K. Hinton, S. R. Hollowood, D. L. Honscheid, K. Huterer, D. James, D. J. Kuehn, K. Lahav, O. Lee, S. Lin, H. Marshall, J. L. Mena-Fernández, J. Menanteau, F. Miquel, R. Muir, J. Ogando, R. L. C. Petravick, D. Malagón, A. A. Plazas Prat, J. Raveri, M. Rykoff, E. S. Samuroff, S. Sanchez, E. Shin, T. Smith, M. Suchyta, E. Swanson, M. E. C. Tarle, G. Thomas, D. To, C. Tucker, D. L. Vikram, V. Yamamoto, M. Cosmology and Nongalactic Astrophysics 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) 3x2pt cosmology analysis. The 3x2pt 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 (Balrog) 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. 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.
title	Dark Energy Survey Year 6 Results: Redshift Calibration of the MagLim++ Lens Sample
topic	Cosmology and Nongalactic Astrophysics
url	https://arxiv.org/abs/2509.07964