Identifying Dwarfs of MC Analog GalaxiEs (ID-MAGE): The Search for Satellites around Low-mass Hosts

August 2025 • 2025ApJ...989...58H

Authors • Hunter, Laura Congreve • Mutlu-Pakdİl, Burçİn • Sand, David J. • Bennet, Paul • Khim, Donghyeon J. • Crnojević, Denija • Doliva-Dolinsky, Amandine • Durodola, Emmanuel • Fielder, Catherine • Goebel-Bain, Rowan • Jones, Michael G. • Karunakaran, Ananthan • Spekkens, Kristine • Zaritsky, Dennis

Abstract • We present results from Identifying Dwarfs of MC Analog GalaxiEs (ID-MAGE), a survey aimed at identifying and characterizing unresolved satellite galaxies around 35 nearby LMC- and SMC-mass hosts (D = 4−10 Mpc). We use archival DESI Legacy Survey imaging data and perform an extensive search for dwarf satellites, extending out to a radius of 150 kpc (∼R_vir). We identify 355 candidate satellite galaxies, including 264 new discoveries. Extensive tests with injected galaxies demonstrate that the survey is complete down to M_V ∼ −9.0 (assuming the distance of the host) and μ_0,V ∼ 26 mag arcsec⁻² (assuming an n = 1 Sérsic profile). We perform consistent photometry, via Sérsic profile fitting, on all candidates and have initiated a comprehensive follow-up campaign to confirm and characterize candidates. Through a systematic visual inspection campaign, we classify the top candidates as high-likelihood satellites. On average, we find 4.0 ± 1.4 high-likelihood candidate satellites per LMC-mass host and 2.1 ± 0.6 per SMC-mass host, which is within the range predicted by cosmological models. We use this sample to establish upper and lower estimates on the satellite luminosity function of LMC-/SMC-mass galaxies. ID-MAGE nearly triples the number of low-mass galaxies surveyed for satellites with well-characterized completeness limits, providing a unique data set to explore small-scale structure and dwarf galaxy evolution around low-mass hosts in diverse environments.

Links

• PREPRINT http://arxiv.org/abs/2504.00253
• ELECTR https://doi.org/10.3847/1538-4357/ade9a4
• SIMBAD https://simbad.u-strasbg.fr/simbad/sim-ref?querymethod=bib&simbo=on&submit=submit+bibcode&bibcode=2025ApJ...989...58H
• PDF https://iopscience.iop.org/article/10.3847/1538-4357/ade9a4/pdf
• DATA https://doi.org/10.5281/zenodo.15498887