Galaxy and mass assembly (GAMA): from filaments to voids, how extreme environment affects gas metallicity and SFR in galaxies

Abstract

Context. The stellar mass−metallicity (M⋆–Z) and stellar mass−star formation rate (M⋆–SFR) relations are fundamental tools for understanding the evolution of star-forming (SF) galaxies. Combined with environmental factors, these relations provide valuable insights into how galaxies evolve. Aims. We analysed the M⋆–Z and M⋆–SFR relations for SF galaxies, classified according to their environment, and compared them with a control sample of field galaxies. The aim was to quantify the differences in metallicity (ΔZ) and star formation rate (ΔSFR) among galaxies in different environments. To achieve this, we used data from the Galaxy And Mass Assembly (GAMA) survey, along with the filament catalogue that classifies galaxies into filaments, tendrils, and voids. Methods. The emission lines were corrected for dust extinction, SF galaxies were selected using the BPT diagram, and their Z and SFR were estimated. Control samples were created for each type of environment, using field galaxies. The M⋆–Z and M⋆–SFR relations were fitted using Bayesian and least-squares methods. The scaling relations for galaxies in different environments were compared to their corresponding control samples to establish robust differences. Results. We determined that ΔZ increases as environments become denser. On the contrary, ΔSFR increases as environments become less dense. Both results demonstrate significant differences between filaments and tendrils compared to voids. We also analysed galaxies in filaments and tendrils that do not belong to any group, and found little to no difference compared to their control sample. Morphology showed no significant deviation from the control sample. Conclusions. We find that galaxies in filaments and tendrils have higher metallicities and lower SFRs due to enriched environments, while void galaxies sustain high SFRs with low metallicities, likely driven by isolation and cold gas accretion. Our results indicate that local environmental factors, rather than large-scale structure, are the primary drivers of these differences.