The MAGPI survey: Science goals, design, observing strategy, early results and theoretical framework

Abstract

We present an overview of the Middle Ages Galaxy Properties with Integral Field Spectroscopy (MAGPI) survey, a Large Program on the European Southern Observatory Very Large Telescope. MAGPI is designed to study the physical drivers of galaxy transformation at a lookback time of 3–4 Gyr, during which the dynamical, morphological, and chemical properties of galaxies are predicted to evolve significantly. The survey uses new medium-deep adaptive optics aided Multi-Unit Spectroscopic Explorer (MUSE) observations of fields selected from the Galaxy and Mass Assembly (GAMA) survey, providing a wealth of publicly available ancillary multi-wavelength data. With these data, MAGPI will map the kinematic and chemical properties of stars and ionised gas for a sample of 60 massive ( ${>}7 \times 10^{10} {\mathrm{M}}_\odot$ ) central galaxies at $0.25 < z <0.35$ in a representative range of environments (isolated, groups and clusters). The spatial resolution delivered by MUSE with Ground Layer Adaptive Optics ( $0.6-0.8$ arcsec FWHM) will facilitate a direct comparison with Integral Field Spectroscopy surveys of the nearby Universe, such as SAMI and MaNGA, and at higher redshifts using adaptive optics, for example, SINS. In addition to the primary (central) galaxy sample, MAGPI will deliver resolved and unresolved spectra for as many as 150 satellite galaxies at $0.25 < z <0.35$ , as well as hundreds of emission-line sources at $z < 6$ . This paper outlines the science goals, survey design, and observing strategy of MAGPI. We also present a first look at the MAGPI data, and the theoretical framework to which MAGPI data will be compared using the current generation of cosmological hydrodynamical simulations including EAGLE, Magneticum, HORIZON-AGN, and Illustris-TNG. Our results show that cosmological hydrodynamical simulations make discrepant predictions in the spatially resolved properties of galaxies at $z\approx 0.3$ . MAGPI observations will place new constraints and allow for tangible improvements in galaxy formation theory.

The origin of star–gas misalignments in simulated galaxies

“…With the advent of large IFU galaxy surveys at intermediate cosmic times (e.g. the Middle Ages Galaxy Properties with Integral Field Spectroscopy, MAGPI, Foster et al 2021), it will be possible to measure the misalignment fraction at z>0 and test these predictions. Fig.…”

Different higher-order kinematics between star-forming and quiescent galaxies based on the SAMI, MAGPI and LEGA-C surveys

“…The survey is ongoing, but the program has already obtained fully reduced data for thirty-five fields, though in this work we use only the first fifteen. An overview of the observations and data reduction is provided in the survey paper (Foster et al 2021), while the full data reduction pipeline (based on the MUSE pipeline, Weilbacher et al 2020 and on the Zurich Atmosphere Purge sky-subtraction software, Soto et al 2016), will be described in an upcoming work (Mendel et al, in prep.). Each MAGPI cube is segmented into 'minicubes', centred on individual galaxy detections.…”

“…In this work, we use high-quality optical spectroscopy from the local SAMI Galaxy Survey, from the MAGPI Survey (Foster et al 2021, redshift z = 0.3) and from the LEGA-C Survey (van der Wel et al 2014, z = 0.8), to investigate the link between star-forming status and higher-order kinematics. We start by showing the relation between spatially resolved h4 and the value integrated inside an aperture ( § 2).…”

The SAMI Galaxy Survey: Environmental analysis of the orbital structures of passive galaxies

“…Undertaking similar analysis in galaxies at higher redshifts (e.g. using the MAGPI survey - Foster et al 2021) would also help to isolate the evolutionary effect of environment on the stellar kinematics of galaxies.…”