Instituto de Astrofísica e Ciências do Espaço

The MAGPI survey: emission-line products data release and the role of spectroscopic aperture covering fraction on the Balmer decrement-stellar mass relation

A. J. Battisti, E Muller, E Wisnioski, J. T. Mendel, C. Foster, C. P. Lagos, K. E. Harborne, I Aalia, S Barsanti, I. P. Breda, D. Calzetti, S. M. Croom, P Das, A. Ferré-Mateu, T Gao, E Gjergo, K. Grasha, Y Mai, A Mailvaganam, T. Mukherjee, M Mun, R. S. Remus, G. Sharma, S. M. Sweet, S. Thater, L. M. Valenzuela, J. van de Sande, G. van de Ven, T. Zafar, B. Ziegler

Abstract
The 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 $0.05 \leq z_{s p e c} \leq 0.424$ ( $H α$ -window) and aperture-based emission-line measurements for 2607 galaxies at $0.05 \leq z_{s p e c} \leq 1.50$ (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 ( $f_{c}$ ) has on the relationship between the Balmer decrement ( $B D = F (H α) / F (H β)$ ; a common proxy for dust attenuation) and the total stellar mass ( $M_{⋆}$ ). Several studies have suggested that the BD-- $M_{⋆}$ relation may be redshift invariant; however, the compared surveys often have different $f_{c}$ due to their differing fibre or slit sizes that can cause systematic offsets. Our results indicate that $f_{c}$ has a significant impact on this relationship, due to galaxies having negative BD radial gradients, which are more negative for more massive galaxies at $z ≲ 0.4$ . Comparing spectroscopic surveys with $⟨ f_{c} ⟩ ≳ 0.5$ , we find that the BD-- $M_{⋆}$ relation shows a preference for redshift evolution and is roughly consistent with the behaviour of ultraviolet stellar continuum attenuation redshift evolution ( $A_{F U V}$ -z), with the average dust attenuation in galaxies peaking at $z \sim 1.2$ and decreasing at lower and higher redshifts.

Keywords
surveys / astronomical data bases: miscellaneous / dust / extinction / ISM: general / galaxies: general

Monthly Notices of the Royal Astronomical Society
Volume 552, Issue stag1585, Page 25
2026 October

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