Galaxies evolve through a dynamic exchange of material with their immediate surrounding environment, the so-called circumgalactic medium (CGM). Understanding the physics of gas flows and the nature of the CGM is thus fundamental to studying galaxy evolution, especially at $4 \leq z \leq 6$ (i.e. at post-Reionization Epoch) when galaxies rapidly assembled their masses and reached their chemical maturity. Galactic outflows are predicted to enrich the CGM with metals, although gas stripping in systems undergoing a major merger has also been suggested to play a role. In this work, we explore the metal enrichment of the medium around merging galaxies at $z \sim 4.5$, observed by the ALMA Large Program to INvestigate [CII] at Early times (ALPINE). To do so, we study the nature of the [CII]158 $μ$m emission in the CGM around these systems, using simulations to help disentangle the mechanisms contributing to the CGM metal pollution. By adopting an updated classification of major merger systems in the ALPINE survey, we select and analyze merging galaxies whose components can be spatially and/or spectrally resolved in a robust way. Thus, we can distinguish between the [CII] emission coming from the single components of the system and that coming from the system as a whole. We also make use of the \texttt{dustyGadget} cosmological simulation to select synthetic analogs of observed galaxies and guide the interpretation of the observational results. We find a large diffuse [CII] envelope ($\gtrsim 20 $ kpc) embedding all the merging systems, with at least $25 \%$ of the total [CII] emission coming from the medium \textit{between} the galaxies. Using predictions from \texttt{dustyGadget} we suggest that this emission has a multi-fold nature, with dynamical interactions between galaxies playing a major role in stripping the gas and enriching the medium with heavy elements.}
Photochemistry in the inner layers of clumpy circumstellar envelopes: formation of water in C-rich objects and of C-bearing molecules in O-rich objects
The impact of surface acetylene cyclotrimerization on the abundance of aromatic hydrocarbons in carbon-rich asymptotic giant branch stars
Institute of Astronomy of Russian Academy of Sciences（俄罗斯科学院天文学研究所）；Lomonosov Moscow State University（莫斯科国立罗蒙诺索夫大学）；Skolkovo Institute of Science and Technology（斯科尔科沃科学技术学院）；Samara Branch of P. N. Lebedev Physical Institute of the Russian Academy of Sciences（俄罗斯科学院列别杰夫物理研究所萨马拉分部）；Ural Federal University（乌拉尔联邦大学）
