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Main Authors: Sand, D. J., Mutlu-Pakdil, B., Jones, M. G., Karunakaran, A., Andrews, J. E., Bennet, P., Crnojevic, D., Donatiello, G., Drlica-Wagner, A., Fielder, C., Martinez-Delgado, D., Martinez-Vazquez, C. E., Spekkens, K., Doliva-Dolinsky, A., Hunter, L. C., Carlin, J. L., Cerny, W., Hai, T. N., McQuinn, K. B. W, Pace, A. B., Smercina, A.
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2409.16345
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author Sand, D. J.
Mutlu-Pakdil, B.
Jones, M. G.
Karunakaran, A.
Andrews, J. E.
Bennet, P.
Crnojevic, D.
Donatiello, G.
Drlica-Wagner, A.
Fielder, C.
Martinez-Delgado, D.
Martinez-Vazquez, C. E.
Spekkens, K.
Doliva-Dolinsky, A.
Hunter, L. C.
Carlin, J. L.
Cerny, W.
Hai, T. N.
McQuinn, K. B. W
Pace, A. B.
Smercina, A.
author_facet Sand, D. J.
Mutlu-Pakdil, B.
Jones, M. G.
Karunakaran, A.
Andrews, J. E.
Bennet, P.
Crnojevic, D.
Donatiello, G.
Drlica-Wagner, A.
Fielder, C.
Martinez-Delgado, D.
Martinez-Vazquez, C. E.
Spekkens, K.
Doliva-Dolinsky, A.
Hunter, L. C.
Carlin, J. L.
Cerny, W.
Hai, T. N.
McQuinn, K. B. W
Pace, A. B.
Smercina, A.
contents 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$10$^5$ $L_{\odot}$) 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$10$^5$ $L_{\odot}$) 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.
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id arxiv_https___arxiv_org_abs_2409_16345
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publishDate 2024
record_format arxiv
spellingShingle Three Quenched, Faint Dwarf Galaxies in the Direction of NGC 300: New Probes of Reionization and Internal Feedback
Sand, D. J.
Mutlu-Pakdil, B.
Jones, M. G.
Karunakaran, A.
Andrews, J. E.
Bennet, P.
Crnojevic, D.
Donatiello, G.
Drlica-Wagner, A.
Fielder, C.
Martinez-Delgado, D.
Martinez-Vazquez, C. E.
Spekkens, K.
Doliva-Dolinsky, A.
Hunter, L. C.
Carlin, J. L.
Cerny, W.
Hai, T. N.
McQuinn, K. B. W
Pace, A. B.
Smercina, A.
Astrophysics of Galaxies
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$10$^5$ $L_{\odot}$) 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$10$^5$ $L_{\odot}$) 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.
title Three Quenched, Faint Dwarf Galaxies in the Direction of NGC 300: New Probes of Reionization and Internal Feedback
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2409.16345