Star formation rates. Left: Measured [O II] flux versus SDSS r magnitude recomputed with PHOTUTILS. The full MEGAFLOW sample is represented with gray dots. Colored and black dots represent, respectively, the primary galaxies that are associated and not associated with a counterpart absorption. Galaxies with no detected [O II] flux are represented by downward arrows. Right: Estimated stellar mass versus estimated SFR for the primary galaxies. The top and right histograms present respectively the stellar mass distribution and the SFR distribution for the galaxies associated (orange) and not associated (gray) with a Mg II absorption. Arrows on the left indicates galaxies without stellar mass estimation and/or no SFR estimation (because no [O II] emission detected). The primary galaxies associated with an absorption are colored according to the Mg II absorption rest-frame equivalent width. Error bars are 1σ uncertainties.