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Autores principales: Hsu, Y. -H., Gruen, D., Gallardo, P. A., Dolag, K., To, C. -H., Wu, H. -Y., Marini, I., Rozo, E.
Formato: Preprint
Publicado: 2025
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Acceso en línea:https://arxiv.org/abs/2505.14791
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author Hsu, Y. -H.
Gruen, D.
Gallardo, P. A.
Dolag, K.
To, C. -H.
Wu, H. -Y.
Marini, I.
Rozo, E.
author_facet Hsu, Y. -H.
Gruen, D.
Gallardo, P. A.
Dolag, K.
To, C. -H.
Wu, H. -Y.
Marini, I.
Rozo, E.
contents The pairwise Kinematic Sunyaev-Zel'dovich (kSZ) measures both the pairwise motion between massive groups and the amount of gas within them, providing a tracer for the cosmic growth. To interpret the cosmological information in kSZ, it is crucial to understand the optical cluster selection bias on the kSZ observables. Line-of-sight structures that contribute to both the optical observable (e.g. richness) and the kSZ signal can induce a correlation between these two quantities at fixed cluster mass. The selection bias arising from this correlation is a key systematic effect for cosmological analyses and has the potential to resolve the tension between the cosmological constraints from the DES-Y1 cluster counts, lensing, and Planck. In order to test for a kSZ equivalent of such a bias, we adopt an alternative mock richness based on galaxy counts within cylindrical volumes along the line-of-sight. We apply the cylindrical count method to hydrodynamical simulations across a wide range of galaxy selection criteria, assigning richness consistent with DES-Y1 to the mock clusters. We find no significant bias on pairwise kSZ, pairwise velocities, or optical depth, when comparing optically selected clusters to mass-selected halos, within our uncertainty limits of approximately 16, 10, and 8 per cent, respectively.
format Preprint
id arxiv_https___arxiv_org_abs_2505_14791
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Robustness of Pairwise Kinematic SZ Effect to Optical Cluster Selection Bias
Hsu, Y. -H.
Gruen, D.
Gallardo, P. A.
Dolag, K.
To, C. -H.
Wu, H. -Y.
Marini, I.
Rozo, E.
Cosmology and Nongalactic Astrophysics
The pairwise Kinematic Sunyaev-Zel'dovich (kSZ) measures both the pairwise motion between massive groups and the amount of gas within them, providing a tracer for the cosmic growth. To interpret the cosmological information in kSZ, it is crucial to understand the optical cluster selection bias on the kSZ observables. Line-of-sight structures that contribute to both the optical observable (e.g. richness) and the kSZ signal can induce a correlation between these two quantities at fixed cluster mass. The selection bias arising from this correlation is a key systematic effect for cosmological analyses and has the potential to resolve the tension between the cosmological constraints from the DES-Y1 cluster counts, lensing, and Planck. In order to test for a kSZ equivalent of such a bias, we adopt an alternative mock richness based on galaxy counts within cylindrical volumes along the line-of-sight. We apply the cylindrical count method to hydrodynamical simulations across a wide range of galaxy selection criteria, assigning richness consistent with DES-Y1 to the mock clusters. We find no significant bias on pairwise kSZ, pairwise velocities, or optical depth, when comparing optically selected clusters to mass-selected halos, within our uncertainty limits of approximately 16, 10, and 8 per cent, respectively.
title Robustness of Pairwise Kinematic SZ Effect to Optical Cluster Selection Bias
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2505.14791