Structure and Large Scale Environment of Galaxy Pairs in the S-PLUS DR4

In this paper, we use photometric data from the S-PLUS DR4 survey to identifyisolated galaxy pairs and analyse their characteristics and properties. Ourresults align with previous spectroscopic studies, particularly in luminosityfunction parameters, suggesting a consistent trait among galaxy systems. Ourfindings reveal a high fraction of red galaxies across all samples,irrespective of projected distance, velocity difference, or luminosity ratio.We found that the proximity of a neighbour to its central galaxy influences itscolour due to environmental effects. We also found that central and neighbourhave different behaviours: central galaxies maintain a stable red colourregardless of luminosity, while neighbour colours vary based on luminosityratios. When the central is significantly brighter, the neighbour tends to beless red. According to our division in red, blue and mixed pairs, we foundevidence of galactic conformity. Red pair fractions increase in closer pairsand in pairs of similar luminosity, indicating shared environments promotingred galaxy formation. Analysing local density, the expected colour-densityrelation is of course recovered, but it is strongly determined by the stellarmass of the pair. In denser environments, the red pair fractions increase, bluepairs decrease and for mixed pairs it depends on their stellar mass: moremassive mixed pairs decrease their fraction whereas the lower massive onesincrease it. These results shed light on the intricate relationship betweengalaxy pairs, their characteristics, and environmental influences on colour,providing insights into their evolutionary histories.