Group Pre-processing in J1611+4026: Minor Rejuvenation of a Massive ETG fueled by Interaction-driven Gas Transfer

Abstract

Interactions within galaxy groups are fundamental drivers of galactic evolution, and establishing a direct observational link between the dynamical processes of satellite galaxies and the rejuvenation of massive host galaxies remains challenging. We present a multi-wavelength work of J1611+4026, a unique triple system characterised by a massive early-type host galaxy, Component C and two gas-rich companions, Components A and B, which are currently undergoing a major merger in its near environment. Utilising deep optical imaging from DESI-LS and spectroscopic data from DESI and P200, we employ 2D morphological decomposition using \textsc{GALIGHT} alongside joint spectrophotometric synthesis modelling with \textsc{BAGPIPES} and \textsc{CIGALE} to deconstruct the structural properties and star formation histories of the member galaxies. Crucially, we identify an asymmetric tidal tail extending $\sim$15.15 kpc from Component A, confirming the ongoing interaction between the companions. Although Component C appears quiescent in both morphology and spectroscopy, we reveal a subtle robust signal of ``minor rejuvenation'', characterised by significant internal dust extinction of $E(B-V) \sim 0.53$ and a UV excess. The reconstructed star formation history indicates a recent ($\sim$100 Myr) starburst that contributes a negligible fraction to the total stellar mass ($f_{\rm burst} < 0.1$ per cent). We propose that this activity is fueled by the accretion of metal-enriched gas stripped from the interacting companions. These results strongly suggest group pre-processing, where interactions between satellite galaxies drive low-level star formation in the massive host through gas transfer, providing a quantitative benchmark for interaction-driven evolution in dense environments.