DELVE Milky Way Satellite Census I: Satellite Population and Survey Selection Function

Journal Article · Mon Sep 15 04:00:00 EDT 2025 · No journal information

OSTI ID:2997195

Tan, Chin Yi ^[1]; Drlica-Wagner, A. ^[2]; Pace, A. B. ^[3]; Cerny, W. ^[4]; Nadler, E. O. ^[5]; Doliva-Dolinsky, A. ^[6]; Li, T. S. ^[7]; Simon, J. D. ^[8]; Vivas, A. K. ^[9]; Walker, Alistair ^[9]; Adamów, M. ^[10]; Anbajagane, D. ^[11]; Bechtol, K. ^[12]; Carlin, J. L. ^[13]; Casey, Q. O. ^[14]; Chang, C. ^[11]; Chaturvedi, A. ^[6]; Cheng, Ting-Yun ^[15]; Chiti, A. ^[16]; Choi, Y. ^[17] ; Crnojević, D. ^[18]; Ferguson, P. S. ^[19]; Gruendl, R. A. ^[20]; Ji, A. P. ^[21]; Limberg, G. ^[22]; Medina, G. E. ^[7]; Mutlu-Pakdil, B. ^[14]; Overdeck, K. ^[23]; Placco, V. M. ^[17]; Noël, N. E.D. ^[6]; Riley, A. H. ^[24]; Sand, D. J. ^[25]; Sharp, J. ^[26]; Sherman, N. F. ^[27]; Stringfellow, G. S. ^[28]; Wechsler, R. H. ^[29]; Aguena, Michel ^[30]; Allam, Sahar ^[31]; Alves, Otavio ^[32]; Bacon, David ^[33]; Brooks, David ^[34]; Burke, David ^[35]; Camilleri, Ryan ^[36]; Carballo-Bello, J. A. ^[37]; Carnero Rosell, Aurelio ^[38]; Carretero, Jorge ^[39]; da Costa, Luiz ^[40]; da Silva Pereira, Maria daiana ^[41]; Davis, Tamara ^[36]; De Vicente, Juan ^[42]; Desai, Shantanu ^[43]; Everett, Spencer ^[44]; Flaugher, Brenna ^[31]; Frieman, Josh ^[45]; Garcia-Bellido, Juan ^[46]; Gruen, Daniel ^[47]; Gutierrez, Gaston ^[31]; Herner, Kenneth ^[31]; Hinton, Samuel ^[36]; Hollowood, Devon L. ^[48]; James, D. J. ^[49]; Kuehn, Kyler ^[50]; Lahav, Ofer ^[34]; Lee, Sujeong ^[51]; Marshall, Jennifer ^[52]; Martínez-Vázquez, C. E. ^[53]; Massana, P. ^[54]; Mena-Fernández, Juan ^[55]; Miquel, Ramon ^[56]; Muir, Jessica ^[57]; Myles, Justin ^[58]; Ogando, Ricardo ^[59]; Plazas Malagón, Andrés ^[35]; Porredon, Anna ^[60]; Sanchez, Eusebio ^[42]; Sanchez Cid, David ^[61]; Sevilla, Ignacio ^[42]; Smith, Mathew ^[62]; Suchyta, Eric ^[63]; Swanson, Molly ^[10]; To, Chun-Hao ^[26]; Tollerud, E. J. ^[64]; Tucker, Douglas ^[31]; Vikram, Vinu ^[65]; Weaverdyck, Noah ^[66]; Yamamoto, Masaya ^[67]; Zenteno, A. ^[9]

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1. Chicago U., KICP; Chicago U.; SkAI, Chicago
2. Fermilab; Chicago U., KICP; Chicago U., Astron. Astrophys. Ctr.; SkAI, Chicago
3. Virginia U., Astron. Dept.
4. Yale U., Math. Dept.
5. UC, San Diego
6. Surrey U.
7. Toronto U., Astron. Dept.
8. Carnegie Inst. Observ.
9. Cerro-Tololo InterAmerican Obs.
10. Illinois U., Urbana (main)
11. Chicago U., Astron. Astrophys. Ctr.; Chicago U., KICP; SkAI, Chicago
12. Wisconsin U., Madison
13. NOAO, Tucson
14. Dartmouth Coll.
15. Kapteyn Astron. Inst., Groningen
16. Chicago U., Astron. Astrophys. Ctr.; Chicago U., KICP
17. Natl. Solar Observ., Tucson
18. South Florida U.
19. Washington U., Seattle; Wisconsin U., Madison
20. Illinois U., Urbana, Astron. Dept.; Illinois U., Urbana (main)
21. Chicago U., KICP; Chicago U., Astron. Astrophys. Ctr.
22. Chicago U., KICP
23. Chicago U.; SkAI, Chicago
24. Durham U., ICC; Lund U.
25. Arizona U., Astron. Dept. - Steward Observ.
26. Chicago U., Astron. Astrophys. Ctr.
27. Boston U.
28. Colorado U., CASA
29. Stanford U.; KIPAC, Menlo Park; SLAC
30. Trieste Observ.; LIneA, Rio de Janeiro
31. Fermilab
32. U. Michigan, Ann Arbor
33. Portsmouth U., ICG
34. University Coll. London
35. KIPAC, Menlo Park; SLAC
36. Queensland U.
37. Tarapaca U.
38. IAC, La Laguna; LIneA, Rio de Janeiro; Laguna U., Tenerife
39. Barcelona, IFAE
40. LIneA, Rio de Janeiro
41. Hamburg Observ.
42. Madrid, CIEMAT
43. Indian Inst. Tech., Hyderabad
44. Caltech
45. Chicago U., Astron. Astrophys. Ctr.; Fermilab; Chicago U., KICP
46. Madrid, IFT
47. Munich U., ASC
48. UC, Santa Cruz
49. Unlisted, US, MA; Old Dominion U.; Jefferson Lab; VSEA, Gloucester
50. Australian Astron. Observ.; Lowell Observ.
51. Caltech, JPL
52. Texas A-M
53. Gemini Observ., Hilo
54. Gemini Observ., La Serena
55. LPSC, Grenoble
56. ICREA, Barcelona; Barcelona, Autonoma U.; Barcelona, IFAE
57. Cincinnati U.; Perimeter Inst. Theor. Phys.
58. Princeton U., Astrophys. Sci. Dept.
59. Rio de Janeiro Observ.
60. Madrid, CIEMAT; Ruhr U., Bochum
61. Madrid, CIEMAT; Zurich U.
62. Lancaster U.
63. ORNL, Oak Ridge (main)
64. Baltimore, Space Telescope Sci.
65. Calicut U.
66. UC, Berkeley, Astron. Dept.; LBL, Berkeley
67. Princeton U., Astrophys. Sci. Dept.; Duke U.

The properties of Milky Way satellite galaxies have important implications for galaxy formation, reionization, and the fundamental physics of dark matter. However, the population of Milky Way satellites includes the faintest known galaxies, and current observations are incomplete. To understand the impact of observational selection effects on the known satellite population, we perform rigorous, quantitative estimates of the Milky Way satellite galaxy detection efficiency in three wide-field survey datasets: the Dark Energy Survey Year 6, the DECam Local Volume Exploration Data Release 3, and the Pan-STARRS1 Data Release 1. Together, these surveys cover $$\sim$$13,600 deg$^2$ to $$g \sim 24.0$$ and $$\sim$$27,700 deg$^2$ to $$g \sim 22.5$$, spanning $$\sim$$91% of the high-Galactic-latitude sky ($$|b| \geq 15^\circ$$). We apply multiple detection algorithms over the combined footprint and recover 49 known satellites above a strict census detection threshold. To characterize the sensitivity of our census, we run our detection algorithms on a large set of simulated galaxies injected into the survey data, which allows us to develop models that predict the detectability of satellites as a function of their properties. We then fit an empirical model to our data and infer the luminosity function, radial distribution, and size-luminosity relation of Milky Way satellite galaxies. Our empirical model predicts a total of $$265^{+79}_{-47}$$ satellite galaxies with $$-20 \leq M_V \leq 0$$, half-light radii of $$15 \leq r_{1/2} (\rm pc) \leq 3000$$, and galactocentric distances of $$10 \leq D_{\rm GC} (\rm kpc) \leq 300$$. We also identify a mild anisotropy in the angular distribution of the observed galaxies, at a significance of $$\sim$$$$2σ$, which can be attributed to the clustering of satellites associated with the LMC.

• Research Organization: Baltimore, Space Telescope Sci.; Chicago U.; Trieste Observ.; Virginia U., Astron. Dept.; Ruhr U., Bochum; Boston U.; Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Laguna U., Tenerife; Yale U., Math. Dept.; Portsmouth U., ICG; U. Michigan, Ann Arbor; Surrey U.; Madrid, CIEMAT; University Coll. London; Wisconsin U., Madison; IAC, La Laguna; Barcelona, IFAE; Gemini Observ., La Serena; LIneA, Rio de Janeiro; Gemini Observ., Hilo; ICREA, Barcelona; Tarapaca U.; Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Carnegie Inst. Observ.; Lowell Observ.; Chicago U., Astron. Astrophys. Ctr.; Natl. Solar Observ., Tucson; Toronto U., Astron. Dept.; Munich U., ASC; Australian Astron. Observ.; Stanford U.; Lund U.; Indian Inst. Tech., Hyderabad; Texas A-M; Illinois U., Urbana (main); Duke U.; Hamburg Observ.; Kapteyn Astron. Inst., Groningen; Lancaster U.; Cerro-Tololo InterAmerican Obs.; Princeton U., Astrophys. Sci. Dept.; Colorado U., CASA; Rio de Janeiro Observ.; SkAI, Chicago; Calicut U.; UC, Berkeley, Astron. Dept.; South Florida U.; UC, Santa Cruz; VSEA, Gloucester; Barcelona, Autonoma U.; Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Washington U., Seattle; Caltech, JPL; Chicago U., KICP; Zurich U.; NOAO, Tucson; Old Dominion U.; Unlisted, US, MA; Perimeter Inst. Theor. Phys.; Dartmouth Coll.; Arizona U., Astron. Dept. - Steward Observ.; Caltech; Durham U., ICC; SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); UC, San Diego; Cincinnati U.; Madrid, IFT; LPSC, Grenoble; Illinois U., Urbana, Astron. Dept.; Queensland U.
• Sponsoring Organization: US Department of Energy
• DOE Contract Number: 89243024CSC000002
• OSTI ID: 2997195
• Report Number(s): FERMILAB-PUB-25-0573-LDRD-PPD; DES-2025-0909; oai:inspirehep.net:2970131; arXiv:2509.12313
• Journal Information: No journal information, Journal Name: No journal information
• Country of Publication: United States
• Language: English