Baryonic accretion in massive galaxy groups and (proto-)clusters. Left: SFR_IR/BAR fraction versus M_stream/M_h ratio for massive galaxy groups in this work (green dots), Daddi et al. (2022b, black dots), Zhou et al. (2024, red dot), and Coogan et al. (2023, orange dot). Black lines mark the fit from Daddi et al. (2022b). We fit the SFR/BAR–M_stream/M_h relation with all data points and show the best-fit as a green line. The black cross in the top-left corner shows representative errors. The solid lines show a model with bending at M_stream > M_h, and the dashed lines show a model with a single trend. The dotted blue line shows the separation between the hot accretion and cold stream regimes. Right: dark matter halo mass versus redshift for this sample and the samples from Daddi et al. (2022b), Zhou et al. (2024), and Coogan et al. (2023), overlaid with dotted and dashed lines separating the three regimes of gas inflow from Dekel & Birnboim (2006), Mandelker et al. (2020), and Daddi et al. (2022a).