Three Quenched, Faint Dwarf Galaxies in the Direction of NGC 300: New Probes of Reionization and Internal Feedback

Journal Article · Tue Sep 24 00:00:00 EDT 2024 · No journal information

DOI:https://doi.org/10.3847/2041-8213/ad927c· OSTI ID:2563251

Sand, David J. ^[1]; Mutlu-Pakdıl, Burçın ^[2]; Jones, Michael G. ^[1]; Karunakaran, Ananthan ^[3]; Andrews, Jennifer E. ^[4]; Bennet, Paul ^[5]; Crnojević, Denija ^[6]; Donatiello, Giuseppe ^[7]; Drlica-Wagner, Alex ^[8]; Fielder, Catherine ^[1]; Martínez-Delgado, David ^[9]; Martínez-Vázquez, Clara E. ^[4]; Spekkens, Kristine ^[10]; Doliva-Dolinsky, Amandine ^[11]; Hunter, Laura C. ^[2]; Carlin, Jeffrey L. ^[12]; Cerny, William ^[13]; Hai, Tehreem N. ^[14]; McQuinn, Kristen B.W. ^[15]; Pace, Andrew B. ^[16] ; Smercina, Adam ^[5]

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1. Arizona U.
2. Dartmouth Coll.
3. Toronto U., Astron. Dept.
4. Gemini Observ., Hilo
5. Baltimore, Space Telescope Sci.
6. Tampa U.
7. INRIM, Turin
8. Fermilab; Chicago U., KICP; Chicago U., Astron. Astrophys. Ctr.
9. CEFCA, Teruel; Zaragoza, ITA
10. Queen's U., Kingston
11. Tampa U.; Dartmouth Coll.
12. NOAO, Tucson
13. Yale U.
14. Rutgers U., Piscataway
15. Baltimore, Space Telescope Sci.; Rutgers U., Piscataway
16. Virginia U., Astron. Dept.

We report the discovery of three faint and ultra-faint dwarf galaxies -- Sculptor A, Sculptor B and Sculptor C -- in the direction of NGC 300 (D=2.0 Mpc), a Large Magellanic Cloud-mass galaxy. Deep ground-based imaging with Gemini/GMOS resolves all three dwarf galaxies into stars, each displaying a red giant branch indicative of an old, metal-poor stellar population. No young stars or HI gas are apparent, and the lack of a GALEX UV detection suggests that all three systems are quenched. Sculptor C (D=2.04$$^{+0.10}_{-0.13}$$ Mpc; $$M_V=-9.1\pm 0.1$$ mag or $$L_V=(3.7^{+0.4}_{-0.3})\times 10^5L_{\odot})$$ is consistent with being a satellite of NGC 300. Sculptor A (D=1.35$$^{+0.22}_{-0.08}$$ Mpc; $$M_V=-6.9\pm 0.3$$ mag or $$L_V=(5^{+1}_{-1})\times 10^4 L_{\odot})$$ is likely in the foreground of NGC 300 and at the extreme edge of the Local Group, analogous to the recently discovered ultra-faint Tucana B in terms of its physical properties and environment. Sculptor B (D=2.48$$^{+0.21}_{-0.24}$$ Mpc; $$M_V=-8.1\pm 0.3$$  mag or $$L_V=(1.5^{+0.5}_{-0.4})\times 10^5L_{\odot})$$ is likely in the background, but future distance measurements are necessary to solidify this statement. It is also of interest due to its quiescent state and low stellar mass. Both Sculptor A and B are $$\gtrsim 2-4 r_{vir}$$ from NGC 300 itself. The discovery of three dwarf galaxies in isolated or low-density environments offers an opportunity to study the varying effects of ram pressure stripping, reionization and internal feedback in influencing the star formation history of the faintest stellar systems.

• Research Organization: Arizona U.; Baltimore, Space Telescope Sci.; CEFCA, Teruel; Chicago U., Astron. Astrophys. Ctr.; Chicago U., KICP; Dartmouth Coll.; Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Gemini Observ., Hilo; INRIM, Turin; NOAO, Tucson; Queen's U., Kingston; Rutgers U., Piscataway; Tampa U.; Toronto U., Astron. Dept.; Virginia U., Astron. Dept.; Yale U.; Zaragoza, ITA
• Sponsoring Organization: US Department of Energy
• Grant/Contract Number: 89243024CSC000002; AC02-07CH11359
• OSTI ID: 2563251
• Report Number(s): FERMILAB-PUB-24-1023-PPD; oai:inspirehep.net:2912597; arXiv:2409.16345
• Journal Information: No journal information, Journal Name: No journal information
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
dwarf galaxies
galaxy quenching
quenched galaxies