The NGC 3109 Satellite System: The First Systematic Resolved Search for Dwarf Galaxies Around an SMC-mass Host
Amandine Doliva-Dolinsky, Burçı̇n Mutlu-Pakdı̇l, Denija Crnojević, Dhayaa Anbajagane, Jeffrey L. Carlin, Jonah Medoff, David J. Sand, Erik Tollerud, Sungsoon Lim, Paul Bennet, A. Drlica-Wagner, Catherine E. Fielder, Jonathan R. Hargis, Kai Herron, Laura E. Hunter, Michael G. Jones, Ananthan Karunakaran, Annika H. G. Peter, Aaron J. Romanowsky, Kristine Spekkens, Jay Strader, Beth Willman, J. A. Carballo-Bello, W. Cerny, Astha Chaturvedi, Nitya Kallivayalil, C. E. Martínez-Vázquez, G. E. Medina, Noelia E. D. Noël, Andrew B. Pace, A. H. Riley, J. D. Sakowska, Adam Smercina, A. K. Vivas, M. Adamów, Clécio R. Bom, Yumi Choi, P. S. Ferguson, M. Navabi, A. Zenteno
Abstract
Abstract We report the results of the deepest search to date for dwarf galaxies around NGC 3109, a barred spiral galaxy with a mass similar to that of the Small Magellanic Cloud (SMC), using a semiautomated search method. Using the Dark Energy Camera, we survey a region covering a projected distance of ∼70 kpc of NGC 3109 ( D = 1.3 Mpc, R vir ∼ 90 kpc, M ∼ 10 8 M * ) as part of the MADCASH and DELVE-DEEP programs. We introduce a newly developed semiresolved search method, used alongside a resolved search, to identify crowded dwarf galaxies around NGC 3109. Using both approaches, we successfully recover the known satellites Antlia and Antlia B. We identified a promising candidate, which was later confirmed to be a background dwarf through deep follow-up observations. Our detection limits are well defined, with the sample ∼80% complete down to M V ∼ −8.0, and include detections of dwarf galaxies as faint as M V ∼ −6.0. This is the first comprehensive study of a satellite system through resolved stars around an SMC mass host. Our results show that NGC 3109 has more bright ( M V ∼ −9.0) satellites than the mean predictions from cold dark matter models, but well within the host-to-host scatter. A larger sample of LMC/SMC-mass hosts is needed to test whether or not the observations are consistent with current model expectations.