Chin Yi Tan, W. Cerny, Andrew B. Pace, J. A. Sharp, K Overdeck, A. Drlica-Wagner, J. D. Simon, Burçı̇n Mutlu-Pakdı̇l, D. J. Sand, A. M. Senkevich, Denis Erkal, P. S. Ferguson, F. Sobreira, Kaia R. Atzberger, Jeffrey L. Carlin, Anirudh Chiti, Denija Crnojević, Alexander P. Ji, L. C. Johnson, T. S. Li, Guilherme Limberg, C. E. Martínez-Vázquez, G. E. Medina, Vinicius M. Placco, A. H. Riley, Erik Tollerud, A. K. Vivas, T. M. C. Abbott, M Aguena, O. Alves, D. Bacon, S. Bocquet, D. Brooks, D. L. Burke, R Camilleri, J. A. Carballo-Bello, A. Carnero Rosell, J. Carretero, Ting-Yun Cheng, Yumi Choi, L. N. da Costa, M. E. S. Pereira, T. M. Davis, J. De Vicente, S. Desai, P. Doel, S. Everett, B. Flaugher, J. Frieman, J. García-Bellido, D. Gruen, G. Gutierrez, S. R. Hinton, D.L Hollowood, D. J. James, K. Kuehn, S. Lee, J.L Marshall, J. Mena-Fernández, F. Menanteau, R Miquel, J Myles, M. Navabi, David L. Nidever, N. E. D. Noël, R. L. C. Ogando, A. A. Plazas Malagón, A. Porredon, S Samuroff, E. Sánchez, D Sanchez Cid, I Sevilla-Noarbe, M. Smith, G. S. Stringfellow, E. Suchyta, M. E. C. Swanson, V. Vikram, A. R. Walker, A. Zenteno
Abstract We report the discovery of three Milky Way satellite candidates: Carina IV, Phoenix III, and DELVE 7, in the third data release of the DECam Local Volume Exploration survey (DELVE). The candidate systems were identified by cross-matching results from two independent search algorithms. All three are extremely faint systems composed of old, metal-poor stellar populations ( τ ≳ 10 Gyr, [Fe/H] ≲−1.4). Carina IV ( M V = −2.8; r 1/2 = 40 pc) and Phoenix III ( M V = −1.2; r 1/2 = 19 pc) have half-light radii that are consistent with the known population of dwarf galaxies, while DELVE 7 ( M V = 1.2; r 1/2 = 2 pc) is very compact and seems more likely to be a star cluster, though its nature remains ambiguous without spectroscopic follow-up. The Gaia proper motions of stars in Carina IV ( M ⋆ = 225 0 − 830 + 1180 M ⊙ ) indicate that it is unlikely to be associated with the LMC, while DECam CaHK photometry confirms that its member stars are metal poor. Phoenix III ( M ⋆ = 52 0 − 290 + 660 M ⊙ ) is the faintest known satellite in the extreme outer stellar halo ( D GC > 100 kpc), while DELVE 7 ( M ⋆ = 6 0 − 40 + 120 M ⊙ ) is the faintest known satellite with D GC > 20 kpc.