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Direct Measurement of Galaxy Assembly Bias using DESI DR1 Data

Fuente: arXiv

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Main Authors:	Shao, Zhiwei, Zu, Ying, Salcedo, Andrés N., Wang, Jiaqi, Yang, Xiaohu, Weinberg, David H., Xu, Xiaoju, Zhai, Zhongxu, Zhang, Zhuowen, Aguilar, J., Ahlen, S., Bianchi, D., Brooks, D., Canning, R., Castander, F. J., Claybaugh, T., Cole, S., Cuceu, A., de la Macorra, A., Dey, Arjun, Doel, P., Ferraro, S., Forero-Romero, J. E., Gaztañaga, E., Gontcho, S. Gontcho A, Gutierrez, G., Honscheid, K., Howlett, C., Huterer, D., Ishak, M., Joyce, R., Kisner, T., Kremin, A., Lahav, O., Lamman, C., Landriau, M., Guillou, L. Le, Levi, M. E., Manera, M., Meisner, A., Miquel, R., Moustakas, J., Nadathur, S., Palanque-Delabrouille, N., Percival, W. J., Prada, F., Pérez-Ràfols, I., Rossi, G., Samushia, L., Sanchez, E., Schlegel, D., Silber, J., Sprayberry, D., Tarlé, G., Weaver, B. A., Zhou, R., Zou, H.
Format:	Preprint
Published:	2025
Subjects:	Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics
Online Access:	Acceder al recurso
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_version_	1866912668033482752
author	Shao, Zhiwei Zu, Ying Salcedo, Andrés N. Wang, Jiaqi Yang, Xiaohu Weinberg, David H. Xu, Xiaoju Zhai, Zhongxu Zhang, Zhuowen Aguilar, J. Ahlen, S. Bianchi, D. Brooks, D. Canning, R. Castander, F. J. Claybaugh, T. Cole, S. Cuceu, A. de la Macorra, A. Dey, Arjun Doel, P. Ferraro, S. Forero-Romero, J. E. Gaztañaga, E. Gontcho, S. Gontcho A Gutierrez, G. Honscheid, K. Howlett, C. Huterer, D. Ishak, M. Joyce, R. Kisner, T. Kremin, A. Lahav, O. Lamman, C. Landriau, M. Guillou, L. Le Levi, M. E. Manera, M. Meisner, A. Miquel, R. Moustakas, J. Nadathur, S. Palanque-Delabrouille, N. Percival, W. J. Prada, F. Pérez-Ràfols, I. Rossi, G. Samushia, L. Sanchez, E. Schlegel, D. Silber, J. Sprayberry, D. Tarlé, G. Weaver, B. A. Zhou, R. Zou, H.
author_facet	Shao, Zhiwei Zu, Ying Salcedo, Andrés N. Wang, Jiaqi Yang, Xiaohu Weinberg, David H. Xu, Xiaoju Zhai, Zhongxu Zhang, Zhuowen Aguilar, J. Ahlen, S. Bianchi, D. Brooks, D. Canning, R. Castander, F. J. Claybaugh, T. Cole, S. Cuceu, A. de la Macorra, A. Dey, Arjun Doel, P. Ferraro, S. Forero-Romero, J. E. Gaztañaga, E. Gontcho, S. Gontcho A Gutierrez, G. Honscheid, K. Howlett, C. Huterer, D. Ishak, M. Joyce, R. Kisner, T. Kremin, A. Lahav, O. Lamman, C. Landriau, M. Guillou, L. Le Levi, M. E. Manera, M. Meisner, A. Miquel, R. Moustakas, J. Nadathur, S. Palanque-Delabrouille, N. Percival, W. J. Prada, F. Pérez-Ràfols, I. Rossi, G. Samushia, L. Sanchez, E. Schlegel, D. Silber, J. Sprayberry, D. Tarlé, G. Weaver, B. A. Zhou, R. Zou, H.
contents	We report the first direct measurement of galaxy assembly bias, a critical systematic in cosmology, from the Dark Energy Spectroscopic Instrument (DESI) Bright Galaxy Survey. We introduce a novel, cosmology-independent method to measure the halo occupation distribution (HOD) by combining a state-of-the-art group catalog with weak gravitational lensing. For groups binned by total luminosity, we determine the galaxy occupation number $N_{\rm gal}$ from group-galaxy cross-correlations, while weak lensing constrains the average halo mass $M_h$. Applying this to a volume-limited sample at $z{\in}[0.05,0.2]$, we measure the dependence of HOD, $N_{\rm gal}(M_h)$, on large-scale overdensity $δ_{g}$. Focusing on the satellite galaxies, we find an assembly bias parameter of $Q_{\rm sat}{=}0.05{\pm}0.14$, a result consistent with zero and in tension with many empirical galaxy formation models. Our method provides a robust approach for characterizing galaxy assembly bias to achieve precision cosmology with DESI and future Stage-V surveys.
format	Preprint
id	arxiv_https___arxiv_org_abs_2510_20896
institution	arXiv
publishDate	2025
record_format	arxiv
spellingShingle	Direct Measurement of Galaxy Assembly Bias using DESI DR1 Data Shao, Zhiwei Zu, Ying Salcedo, Andrés N. Wang, Jiaqi Yang, Xiaohu Weinberg, David H. Xu, Xiaoju Zhai, Zhongxu Zhang, Zhuowen Aguilar, J. Ahlen, S. Bianchi, D. Brooks, D. Canning, R. Castander, F. J. Claybaugh, T. Cole, S. Cuceu, A. de la Macorra, A. Dey, Arjun Doel, P. Ferraro, S. Forero-Romero, J. E. Gaztañaga, E. Gontcho, S. Gontcho A Gutierrez, G. Honscheid, K. Howlett, C. Huterer, D. Ishak, M. Joyce, R. Kisner, T. Kremin, A. Lahav, O. Lamman, C. Landriau, M. Guillou, L. Le Levi, M. E. Manera, M. Meisner, A. Miquel, R. Moustakas, J. Nadathur, S. Palanque-Delabrouille, N. Percival, W. J. Prada, F. Pérez-Ràfols, I. Rossi, G. Samushia, L. Sanchez, E. Schlegel, D. Silber, J. Sprayberry, D. Tarlé, G. Weaver, B. A. Zhou, R. Zou, H. Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics We report the first direct measurement of galaxy assembly bias, a critical systematic in cosmology, from the Dark Energy Spectroscopic Instrument (DESI) Bright Galaxy Survey. We introduce a novel, cosmology-independent method to measure the halo occupation distribution (HOD) by combining a state-of-the-art group catalog with weak gravitational lensing. For groups binned by total luminosity, we determine the galaxy occupation number $N_{\rm gal}$ from group-galaxy cross-correlations, while weak lensing constrains the average halo mass $M_h$. Applying this to a volume-limited sample at $z{\in}[0.05,0.2]$, we measure the dependence of HOD, $N_{\rm gal}(M_h)$, on large-scale overdensity $δ_{g}$. Focusing on the satellite galaxies, we find an assembly bias parameter of $Q_{\rm sat}{=}0.05{\pm}0.14$, a result consistent with zero and in tension with many empirical galaxy formation models. Our method provides a robust approach for characterizing galaxy assembly bias to achieve precision cosmology with DESI and future Stage-V surveys.
title	Direct Measurement of Galaxy Assembly Bias using DESI DR1 Data
topic	Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics
url	https://arxiv.org/abs/2510.20896