Spatial segregation as the origin of anisotropic satellite quenching in haloes and beyond

Zhuoming Zhang; Weiguang Cui; Yun Chen; Romeel Davé

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arXiv · 2609.29739

Spatial segregation as the origin of anisotropic satellite quenching in haloes and beyond

Zhuoming Zhang·Weiguang Cui·Yun Chen·Romeel Davé

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Abstract

Satellite galaxies in massive halos are seen to be preferentially quenched along the major axes of their central galaxies. In contrast, the AGN jet tends to point along the minor axis, which imposes interesting constraints on the role of AGN feedback in satellite galaxy quenching. Here we use the SIMBA, TNG100, EAGLE, and feedback-free SIMBA cosmological simulations at $z=0$ to show that this satellite anisotropy primarily originates from spatial segregation between quenched and unquenched populations. Quenched satellites are more centrally concentrated and more strongly aligned with the central galaxy's major axis, whereas unquenched satellites occupy larger radii and are more nearly isotropic. The persistence of this behaviour without stellar or active galactic nucleus feedback suggests that feedback is not important for satellite quenching. Beyond the halo boundary, the signal varies strongly among simulations and correlates with the excess number of galaxies along the major axis. This links large-scale anisotropic quenching to the direction-dependent distribution of groups, clusters and filamentary environments. Our results provide a unified geometrical interpretation of anisotropic satellite quenching across halo and extra-halo scales.

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Zhuoming Zhang, Weiguang Cui, Yun Chen, Romeel Davé. 2026-09-24. Spatial segregation as the origin of anisotropic satellite quenching in haloes and beyond. https://arxiv.org/abs/2609.29739

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