Battisti, AndrewMuller, EricWisnioski, EmilyMendel, J.TFoster, CLagos, C.D.PHarborne, K.EAalia, I.UBarsanti, SBreda, ICalzetti, DCroom, S.MDas, P.KFerré-Mateu, AGao, TGjergo, EGrasha, KMai, YMailvaganam, AMukherjee, TMun, MRemus, R.-SSharma, GSweet, S.MThater, SValenzuela, L.MVan de Sande, JVan de Ven, GZafar, TZiegler, B2026-10-212026-10-212026Battisti, A.J., Muller, E.G.M., Wisnioski, E., Mendel, J.T., Foster, C., Lagos, C.D.P., Harborne, K.E., Aalia, I.U., Barsanti, S., Breda, I. and Calzetti, D., 2026.10.1093/mnras/stag1585https://hdl.handle.net/10566/25708The Middle Ages Galaxy Properties with Integral field spectroscopy (MAGPI) survey is a Large Program on the European Southern Observatory Very Large Telescope using the Multi Unit Spectroscopic Explorer (MUSE) instrument. This paper presents the data release for the MAGPI emission-line products and includes emission-line maps for 836 galaxies at (Formula presented) ((Formula presented) -window) and aperture-based emission-line measurements for 2607 galaxies at (Formula presented) (upper bound is [O ii] cut-off), both based on the gist software, for all 56 MAGPI fields. We use these data to examine dust attenuation, which represents a major source of uncertainty in the derived properties of galaxies that are critical to constrain models of galaxy evolution. We examine the role that the spectroscopic aperture covering fraction ((Formula presented) ) has on the relationship between the Balmer decrement ((Formula presented) ; a common proxy for dust attenuation) and the total stellar mass ((Formula presented) ). Several studies have suggested that the BD–(Formula presented) relation may be redshift invariant; however, the compared surveys often have different (Formula presented) due to their differing fibre or slit sizes that can cause systematic offsets. Our results indicate that (Formula presented) has a significant impact on this relationship, due to galaxies having negative BD radial gradients, which are more negative for more massive galaxies at (Formula presented). Comparing spectroscopic surveys with (Formula presented), we find that the BD–(Formula presented) relation shows a preference for redshift evolution and is roughly consistent with the behaviour of ultraviolet stellar continuum attenuation redshift evolution ((Formula presented) -z), with the average dust attenuation in galaxies peaking at (Formula presented) and decreasing at lower and higher redshifts.enAstronomical data bases: miscellaneousDustExtinctionGalaxies: generalSurveysArticle