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

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

arXiv · 2504.00253

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

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

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Abstract

We present results from ID-MAGE (Identifying Dwarfs of MC Analog GalaxiEs), a survey aimed at identifying and characterizing unresolved satellite galaxies around 36~nearby LMC- and SMC-mass hosts (D$=$4$-$10~Mpc). We use archival DESI Legacy Survey imaging data and perform an extensive search for dwarf satellites, extending out to a radius of 150~kpc ($\sim$$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\sim-$9.0 (assuming the distance of the host) and $μ_{0,V}\sim$26 mag arcsec$^{-2}$ (assuming a n$=$1 Sérsic profile). We perform consistent photometry, via Sérsic profile fitting, on all candidates and have initiated a comprehensive follow-up campaign to confirm and characterize candidates. Through a systematic visual inspection campaign, we classify the top candidates as high-likelihood satellites. On average, we find 4.0$\pm$1.4 high-likelihood candidate satellites per LMC-mass host and 2.1$\pm$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 dataset to explore small-scale structure and dwarf galaxy evolution around low-mass hosts in diverse environments.

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Laura Congreve Hunter, Burçin Mutlu-Pakdil, David J. Sand, Paul Bennet, Donghyeon J. Khim, Denija Crnojević, Amandine Doliva-Dolinsky, Emmanuel Durodola, Catherine Fielder, Rowan Goebel-Bain, Michael G. Jones, Ananthan Karunakaran, Kristine Spekkens, Dennis Zaritsky. 2026-01-05. Identifying Dwarfs of MC Analog GalaxiEs (ID-MAGE): The Search for Satellites Around Low-Mass Hosts. https://arxiv.org/abs/2504.00253

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