Observational Evidence for Anisotropic Metal Excess around Galaxies
Abstract
The exchange of matter and energy between galaxies and their surroundings drives the cosmic baryon cycle, yet mapping metal transport remains an observational challenge. While simulations predict that galactic winds escape anisotropically along minor axes, evidence for chemical enrichment in neighboring galaxies is limited. We analyze 1,433 galaxy pairs from the Dark Energy Spectroscopic Instrument survey and detect a gas-phase metallicity excess of 14.6% ± 3.7% to 24.2% ± 2.6% in neighbors aligned with the minor axis of massive primary at projected separations of 15--60 kpc, qualitatively consistent with IllustrisTNG simulation. Permutation tests indicate that this excess varies from a marginal detection (>92% confidence) at closer separations (15--30 kpc) to a significant signal (>98% confidence) at intermediate separations (30--60 kpc). Here, we show that these results provide empirical constraints on galactic feedback models and are consistent with a scenario where anisotropic outflows can enrich nearby galaxies, a mechanism that complements other environmental processes.
Versions
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BibTeX
@misc{lyu2026observational,
title = {{Observational Evidence for Anisotropic Metal Excess around Galaxies}},
author = {Cheqiu Lyu and Enci Wang and Zeyu Chen and Chengyu Ma and Yangyao Chen and Haoran Yu and Xu Kong},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2607.24929},
eprint = {2607.24929},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.24929},
}
RIS
TY - UNPB
TI - Observational Evidence for Anisotropic Metal Excess around Galaxies
AU - Cheqiu Lyu
AU - Enci Wang
AU - Zeyu Chen
AU - Chengyu Ma
AU - Yangyao Chen
AU - Haoran Yu
AU - Xu Kong
PY - 2026
DA - 2026/10/20
PB - arXiv
DO - 10.48550/arxiv.2607.24929
UR - https://arxiv.org/abs/2607.24929
AB - The exchange of matter and energy between galaxies and their surroundings drives the cosmic baryon cycle, yet mapping metal transport remains an observational challenge. While simulations predict that galactic winds escape anisotropically along minor axes, evidence for chemical enrichment in neighboring galaxies is limited. We analyze 1,433 galaxy pairs from the Dark Energy Spectroscopic Instrument survey and detect a gas-phase metallicity excess of 14.6% ± 3.7% to 24.2% ± 2.6% in neighbors aligned with the minor axis of massive primary at projected separations of 15--60 kpc, qualitatively consistent with IllustrisTNG simulation. Permutation tests indicate that this excess varies from a marginal detection (>92% confidence) at closer separations (15--30 kpc) to a significant signal (>98% confidence) at intermediate separations (30--60 kpc). Here, we show that these results provide empirical constraints on galactic feedback models and are consistent with a scenario where anisotropic outflows can enrich nearby galaxies, a mechanism that complements other environmental processes.
ER -