Paper
How well does MAGPHYS recover galaxy properties? A test using EAGLE simulated star-forming galaxies
Authors
Zoe R. Jones, Elisabete da Cunha, Andrew Battisti
Abstract
Spectral energy distribution (SED) models are widely used to infer the physical properties of galaxies from multi-wavelength photometry, but their accuracy is difficult to assess because the true properties of observed galaxies are generally unknown. We address this by fitting synthetic SEDs of ~31,000 star-forming galaxies drawn from the EAGLE cosmological simulations, post-processed with the SKIRT radiative transfer code, using the MAGPHYS SED modelling framework. This provides a controlled testbed with known intrinsic parameters, enabling a direct assessment of model accuracy and the origin of systematic biases. Under idealised conditions, fitting well-sampled ultraviolet-to-submillimetre SEDs at z=0.1, z=2, and z=5, MAGPHYS recovers stellar mass, star formation rate, specific star formation rate, dust mass, and dust luminosity to within <~0.14 dex, while mass-weighted stellar ages are not robustly constrained. We find that mismatches between the assumed star formation history (SFH) priors and the intrinsic SFHs of the simulated galaxies introduce systematic biases in stellar mass estimates, even when the fits provide good statistical agreement. To assess performance under realistic survey conditions, we construct a WAVES-like mock sample using optical and near-infrared photometry with realistic uncertainties. In this case, stellar masses and star formation rates remain well constrained (systematic offsets <~0.1 dex; scatters ~0.07 and ~0.15 dex, respectively), whereas dust properties degrade significantly without far-infrared data: dust luminosities show offsets of ~0.30 dex and scatters ~0.25 dex, and dust masses exhibit scatters ~0.3 dex. We conclude that MAGPHYS is a reliable tool for recovering key galaxy properties from broad-band photometry, but that SFH assumptions and limited wavelength coverage introduce significant uncertainties, particularly for dust and stellar ages.
Metadata
Related papers
Fractal universe and quantum gravity made simple
Fabio Briscese, Gianluca Calcagni • 2026-03-25
POLY-SIM: Polyglot Speaker Identification with Missing Modality Grand Challenge 2026 Evaluation Plan
Marta Moscati, Muhammad Saad Saeed, Marina Zanoni, Mubashir Noman, Rohan Kuma... • 2026-03-25
LensWalk: Agentic Video Understanding by Planning How You See in Videos
Keliang Li, Yansong Li, Hongze Shen, Mengdi Liu, Hong Chang, Shiguang Shan • 2026-03-25
Orientation Reconstruction of Proteins using Coulomb Explosions
Tomas André, Alfredo Bellisario, Nicusor Timneanu, Carl Caleman • 2026-03-25
The role of spatial context and multitask learning in the detection of organic and conventional farming systems based on Sentinel-2 time series
Jan Hemmerling, Marcel Schwieder, Philippe Rufin, Leon-Friedrich Thomas, Mire... • 2026-03-25
Raw Data (Debug)
{
"raw_xml": "<entry>\n <id>http://arxiv.org/abs/2603.22945v1</id>\n <title>How well does MAGPHYS recover galaxy properties? A test using EAGLE simulated star-forming galaxies</title>\n <updated>2026-03-24T08:42:39Z</updated>\n <link href='https://arxiv.org/abs/2603.22945v1' rel='alternate' type='text/html'/>\n <link href='https://arxiv.org/pdf/2603.22945v1' rel='related' title='pdf' type='application/pdf'/>\n <summary>Spectral energy distribution (SED) models are widely used to infer the physical properties of galaxies from multi-wavelength photometry, but their accuracy is difficult to assess because the true properties of observed galaxies are generally unknown. We address this by fitting synthetic SEDs of ~31,000 star-forming galaxies drawn from the EAGLE cosmological simulations, post-processed with the SKIRT radiative transfer code, using the MAGPHYS SED modelling framework. This provides a controlled testbed with known intrinsic parameters, enabling a direct assessment of model accuracy and the origin of systematic biases. Under idealised conditions, fitting well-sampled ultraviolet-to-submillimetre SEDs at z=0.1, z=2, and z=5, MAGPHYS recovers stellar mass, star formation rate, specific star formation rate, dust mass, and dust luminosity to within <~0.14 dex, while mass-weighted stellar ages are not robustly constrained. We find that mismatches between the assumed star formation history (SFH) priors and the intrinsic SFHs of the simulated galaxies introduce systematic biases in stellar mass estimates, even when the fits provide good statistical agreement. To assess performance under realistic survey conditions, we construct a WAVES-like mock sample using optical and near-infrared photometry with realistic uncertainties. In this case, stellar masses and star formation rates remain well constrained (systematic offsets <~0.1 dex; scatters ~0.07 and ~0.15 dex, respectively), whereas dust properties degrade significantly without far-infrared data: dust luminosities show offsets of ~0.30 dex and scatters ~0.25 dex, and dust masses exhibit scatters ~0.3 dex. We conclude that MAGPHYS is a reliable tool for recovering key galaxy properties from broad-band photometry, but that SFH assumptions and limited wavelength coverage introduce significant uncertainties, particularly for dust and stellar ages.</summary>\n <category scheme='http://arxiv.org/schemas/atom' term='astro-ph.GA'/>\n <published>2026-03-24T08:42:39Z</published>\n <arxiv:comment>19 pages, 12 figures; Accepted for publication in Monthly Notices of the Royal Astronomical Society</arxiv:comment>\n <arxiv:primary_category term='astro-ph.GA'/>\n <author>\n <name>Zoe R. Jones</name>\n <arxiv:affiliation>International Centre for Radio Astronomy Research</arxiv:affiliation>\n <arxiv:affiliation>Tartu Observatory, University of Tartu, Estonia</arxiv:affiliation>\n </author>\n <author>\n <name>Elisabete da Cunha</name>\n <arxiv:affiliation>International Centre for Radio Astronomy Research</arxiv:affiliation>\n <arxiv:affiliation>ARC Center of Excellence for All Sky Astrophysics in 3 Dimensions</arxiv:affiliation>\n </author>\n <author>\n <name>Andrew Battisti</name>\n <arxiv:affiliation>International Centre for Radio Astronomy Research</arxiv:affiliation>\n <arxiv:affiliation>ARC Center of Excellence for All Sky Astrophysics in 3 Dimensions</arxiv:affiliation>\n <arxiv:affiliation>Research School of Astronomy and Astrophysics, Australian National University, Australia</arxiv:affiliation>\n </author>\n </entry>"
}