The First Tidally Disrupted Ultra-faint Dwarf Galaxy?: A Spectroscopic Analysis of the Tucana III Stream

T. S. Li; J. D. Simon; K. Kuehn; A. B. Pace; D. Erkal; K. Bechtol; B. Yanny; A. Drlica-Wagner; J. L. Marshall; C. Lidman; E. Balbinot; D. Carollo; S. Jenkins; C. E. Martinez-Vázquez; N. Shipp; K. M. Stringer; A. K. Vivas; A. R. Walker; R. H. Wechsler; F. B. Abdalla; S. Allam; J. Annis; S. Avila; E. Bertin; D. Brooks; E. Buckley-Geer; D. L. Burke; A. Carnero Rosell; M. Carrasco Kind; J. Carretero; C. E. Cunha; C. B. D'Andrea; L. N.Da Costa; C. Davis; J. De Vicente; P. Doel; T. F. Eifler; A. E. Evrard; B. Flaugher; J. Frieman; J. Garcia-Bellido; E. Gaztanaga; D. W. Gerdes; D. Gruen; R. A. Gruendl; J. Gschwend; G. Gutierrez; W. G. Hartley; D. L. Hollowood; K. Honscheid; D. J. James; E. Krause; M. A.G. Maia; M. March; F. Menanteau; R. Miquel; A. A. Plazas; E. Sanchez; B. Santiago; V. Scarpine; R. Schindler; M. Schubnell; I. Sevilla-Noarbe; M. Smith; R. C. Smith; M. Soares-Santos; F. Sobreira; E. Suchyta; M. E.C. Swanson; G. Tarle; D. L. Tucker

doi:10.3847/1538-4357/aadf91

The First Tidally Disrupted Ultra-faint Dwarf Galaxy? A Spectroscopic Analysis of the Tucana III Stream

T. S. Li, J. D. Simon, K. Kuehn, A. B. Pace, D. Erkal, K. Bechtol, B. Yanny, A. Drlica-Wagner, J. L. Marshall, C. Lidman, E. Balbinot, D. Carollo, S. Jenkins, C. E. Martinez-Vázquez, N. Shipp, K. M. Stringer, A. K. Vivas, A. R. Walker, R. H. Wechsler, F. B. AbdallaS. Allam, J. Annis, S. Avila, E. Bertin, D. Brooks, E. Buckley-Geer, D. L. Burke, A. Carnero Rosell, M. Carrasco Kind, J. Carretero, C. E. Cunha, C. B. D'Andrea, L. N.Da Costa, C. Davis, J. De Vicente, P. Doel, T. F. Eifler, A. E. Evrard, B. Flaugher, J. Frieman, J. Garcia-Bellido, E. Gaztanaga, D. W. Gerdes, D. Gruen, R. A. Gruendl, J. Gschwend, G. Gutierrez, W. G. Hartley, D. L. Hollowood, K. Honscheid, D. J. James, E. Krause, M. A.G. Maia, M. March, F. Menanteau, R. Miquel, A. A. Plazas, E. Sanchez, B. Santiago, V. Scarpine, R. Schindler, M. Schubnell, I. Sevilla-Noarbe, M. Smith, R. C. Smith, M. Soares-Santos, F. Sobreira, E. Suchyta, M. E.C. Swanson, G. Tarle, D. L. Tucker

Astronomy

Research output: Contribution to journal › Article › peer-review

68 Scopus citations

Abstract

We present a spectroscopic study of the tidal tails and core of the Milky Way satellite Tucana III, collectively referred to as the Tucan III stream, using the 2dF+AAOmega spectrograph on the Anglo-Australian Telescope and the IMACS spectrograph on the Magellan Baade Telescope. In addition to recovering the brightest nine previously known member stars in the Tucana III core, we identify 22 members in the tidal tails.We observe strong evidence for a velocity gradient of 8.0 ± 0.4 km s^-1 deg^-1 over at least 3° on the sky. Based on the continuity in velocity, we confirm that the Tucana III tails are real tidal extensions of Tucana III. The large velocity gradient of the stream implies that Tucana III is likely on a radial orbit. We successfully obtain metallicities for four members in the core and 12 members in the tails. We find that members close to the ends of the stream tend to be more metal-poor than members in the core, indicating a possible metallicity gradient between the center of the progenitor halo and its edge. The spread in metallicity suggests that the progenitor of the Tucana III stream is likely a dwarf galaxy rather than a star cluster. Furthermore, we find that with the precise photometry of the Dark Energy Survey data, there is a discernible color offset between metal-rich disk stars and metal-poor stream members. This metallicity-dependent color offers a more efficient method to recognize metal-poor targets and will increase the selection efficiency of stream members for future spectroscopic follow-up programs on stellar streams.

Original language	English (US)
Article number	22
Journal	Astrophysical Journal
Volume	866
Issue number	1
DOIs	https://doi.org/10.3847/1538-4357/aadf91
State	Published - Oct 10 2018

Keywords

Local Group
dark matter
galaxies: dwarf
galaxies: individual (Tucana III)
stars: abundances

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.3847/1538-4357/aadf91

Cite this

Li, T. S., Simon, J. D., Kuehn, K., Pace, A. B., Erkal, D., Bechtol, K., Yanny, B., Drlica-Wagner, A., Marshall, J. L., Lidman, C., Balbinot, E., Carollo, D., Jenkins, S., Martinez-Vázquez, C. E., Shipp, N., Stringer, K. M., Vivas, A. K., Walker, A. R., Wechsler, R. H., ... Tucker, D. L. (2018). The First Tidally Disrupted Ultra-faint Dwarf Galaxy? A Spectroscopic Analysis of the Tucana III Stream. Astrophysical Journal, 866(1), Article 22. https://doi.org/10.3847/1538-4357/aadf91

Li, TS, Simon, JD, Kuehn, K, Pace, AB, Erkal, D, Bechtol, K, Yanny, B, Drlica-Wagner, A, Marshall, JL, Lidman, C, Balbinot, E, Carollo, D, Jenkins, S, Martinez-Vázquez, CE, Shipp, N, Stringer, KM, Vivas, AK, Walker, AR, Wechsler, RH, Abdalla, FB, Allam, S, Annis, J, Avila, S, Bertin, E, Brooks, D, Buckley-Geer, E, Burke, DL, Rosell, AC, Kind, MC, Carretero, J, Cunha, CE, D'Andrea, CB, Costa, LND, Davis, C, Vicente, JD, Doel, P, Eifler, TF, Evrard, AE, Flaugher, B, Frieman, J, Garcia-Bellido, J, Gaztanaga, E, Gerdes, DW, Gruen, D, Gruendl, RA, Gschwend, J, Gutierrez, G, Hartley, WG, Hollowood, DL, Honscheid, K, James, DJ, Krause, E, Maia, MAG, March, M, Menanteau, F, Miquel, R, Plazas, AA, Sanchez, E, Santiago, B, Scarpine, V, Schindler, R, Schubnell, M, Sevilla-Noarbe, I, Smith, M, Smith, RC, Soares-Santos, M, Sobreira, F, Suchyta, E, Swanson, MEC, Tarle, G & Tucker, DL 2018, 'The First Tidally Disrupted Ultra-faint Dwarf Galaxy? A Spectroscopic Analysis of the Tucana III Stream', Astrophysical Journal, vol. 866, no. 1, 22. https://doi.org/10.3847/1538-4357/aadf91

@article{91fb429245274a7f8c5008df1e12d350,

title = "The First Tidally Disrupted Ultra-faint Dwarf Galaxy?: A Spectroscopic Analysis of the Tucana III Stream",

abstract = "We present a spectroscopic study of the tidal tails and core of the Milky Way satellite Tucana III, collectively referred to as the Tucan III stream, using the 2dF+AAOmega spectrograph on the Anglo-Australian Telescope and the IMACS spectrograph on the Magellan Baade Telescope. In addition to recovering the brightest nine previously known member stars in the Tucana III core, we identify 22 members in the tidal tails.We observe strong evidence for a velocity gradient of 8.0 ± 0.4 km s-1 deg-1 over at least 3° on the sky. Based on the continuity in velocity, we confirm that the Tucana III tails are real tidal extensions of Tucana III. The large velocity gradient of the stream implies that Tucana III is likely on a radial orbit. We successfully obtain metallicities for four members in the core and 12 members in the tails. We find that members close to the ends of the stream tend to be more metal-poor than members in the core, indicating a possible metallicity gradient between the center of the progenitor halo and its edge. The spread in metallicity suggests that the progenitor of the Tucana III stream is likely a dwarf galaxy rather than a star cluster. Furthermore, we find that with the precise photometry of the Dark Energy Survey data, there is a discernible color offset between metal-rich disk stars and metal-poor stream members. This metallicity-dependent color offers a more efficient method to recognize metal-poor targets and will increase the selection efficiency of stream members for future spectroscopic follow-up programs on stellar streams.",

keywords = "Local Group, dark matter, galaxies: dwarf, galaxies: individual (Tucana III), stars: abundances",

author = "Li, {T. S.} and Simon, {J. D.} and K. Kuehn and Pace, {A. B.} and D. Erkal and K. Bechtol and B. Yanny and A. Drlica-Wagner and Marshall, {J. L.} and C. Lidman and E. Balbinot and D. Carollo and S. Jenkins and Martinez-V{\'a}zquez, {C. E.} and N. Shipp and Stringer, {K. M.} and Vivas, {A. K.} and Walker, {A. R.} and Wechsler, {R. H.} and Abdalla, {F. B.} and S. Allam and J. Annis and S. Avila and E. Bertin and D. Brooks and E. Buckley-Geer and Burke, {D. L.} and Rosell, {A. Carnero} and Kind, {M. Carrasco} and J. Carretero and Cunha, {C. E.} and D'Andrea, {C. B.} and Costa, {L. N.Da} and C. Davis and Vicente, {J. De} and P. Doel and Eifler, {T. F.} and Evrard, {A. E.} and B. Flaugher and J. Frieman and J. Garcia-Bellido and E. Gaztanaga and Gerdes, {D. W.} and D. Gruen and Gruendl, {R. A.} and J. Gschwend and G. Gutierrez and Hartley, {W. G.} and Hollowood, {D. L.} and K. Honscheid and James, {D. J.} and E. Krause and Maia, {M. A.G.} and M. March and F. Menanteau and R. Miquel and Plazas, {A. A.} and E. Sanchez and B. Santiago and V. Scarpine and R. Schindler and M. Schubnell and I. Sevilla-Noarbe and M. Smith and Smith, {R. C.} and M. Soares-Santos and F. Sobreira and E. Suchyta and Swanson, {M. E.C.} and G. Tarle and Tucker, {D. L.}",

year = "2018",

month = oct,

day = "10",

doi = "10.3847/1538-4357/aadf91",

language = "English (US)",

volume = "866",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "1",

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TY - JOUR

T1 - The First Tidally Disrupted Ultra-faint Dwarf Galaxy?

T2 - A Spectroscopic Analysis of the Tucana III Stream

AU - Li, T. S.

AU - Simon, J. D.

AU - Kuehn, K.

AU - Pace, A. B.

AU - Erkal, D.

AU - Bechtol, K.

AU - Yanny, B.

AU - Drlica-Wagner, A.

AU - Marshall, J. L.

AU - Lidman, C.

AU - Balbinot, E.

AU - Carollo, D.

AU - Jenkins, S.

AU - Martinez-Vázquez, C. E.

AU - Shipp, N.

AU - Stringer, K. M.

AU - Vivas, A. K.

AU - Walker, A. R.

AU - Wechsler, R. H.

AU - Abdalla, F. B.

AU - Allam, S.

AU - Annis, J.

AU - Avila, S.

AU - Bertin, E.

AU - Brooks, D.

AU - Buckley-Geer, E.

AU - Burke, D. L.

AU - Rosell, A. Carnero

AU - Kind, M. Carrasco

AU - Carretero, J.

AU - Cunha, C. E.

AU - D'Andrea, C. B.

AU - Costa, L. N.Da

AU - Davis, C.

AU - Vicente, J. De

AU - Doel, P.

AU - Eifler, T. F.

AU - Evrard, A. E.

AU - Flaugher, B.

AU - Frieman, J.

AU - Garcia-Bellido, J.

AU - Gaztanaga, E.

AU - Gerdes, D. W.

AU - Gruen, D.

AU - Gruendl, R. A.

AU - Gschwend, J.

AU - Gutierrez, G.

AU - Hartley, W. G.

AU - Hollowood, D. L.

AU - Honscheid, K.

AU - James, D. J.

AU - Krause, E.

AU - Maia, M. A.G.

AU - March, M.

AU - Menanteau, F.

AU - Miquel, R.

AU - Plazas, A. A.

AU - Sanchez, E.

AU - Santiago, B.

AU - Scarpine, V.

AU - Schindler, R.

AU - Schubnell, M.

AU - Sevilla-Noarbe, I.

AU - Smith, M.

AU - Smith, R. C.

AU - Soares-Santos, M.

AU - Sobreira, F.

AU - Suchyta, E.

AU - Swanson, M. E.C.

AU - Tarle, G.

AU - Tucker, D. L.

PY - 2018/10/10

Y1 - 2018/10/10

N2 - We present a spectroscopic study of the tidal tails and core of the Milky Way satellite Tucana III, collectively referred to as the Tucan III stream, using the 2dF+AAOmega spectrograph on the Anglo-Australian Telescope and the IMACS spectrograph on the Magellan Baade Telescope. In addition to recovering the brightest nine previously known member stars in the Tucana III core, we identify 22 members in the tidal tails.We observe strong evidence for a velocity gradient of 8.0 ± 0.4 km s-1 deg-1 over at least 3° on the sky. Based on the continuity in velocity, we confirm that the Tucana III tails are real tidal extensions of Tucana III. The large velocity gradient of the stream implies that Tucana III is likely on a radial orbit. We successfully obtain metallicities for four members in the core and 12 members in the tails. We find that members close to the ends of the stream tend to be more metal-poor than members in the core, indicating a possible metallicity gradient between the center of the progenitor halo and its edge. The spread in metallicity suggests that the progenitor of the Tucana III stream is likely a dwarf galaxy rather than a star cluster. Furthermore, we find that with the precise photometry of the Dark Energy Survey data, there is a discernible color offset between metal-rich disk stars and metal-poor stream members. This metallicity-dependent color offers a more efficient method to recognize metal-poor targets and will increase the selection efficiency of stream members for future spectroscopic follow-up programs on stellar streams.

AB - We present a spectroscopic study of the tidal tails and core of the Milky Way satellite Tucana III, collectively referred to as the Tucan III stream, using the 2dF+AAOmega spectrograph on the Anglo-Australian Telescope and the IMACS spectrograph on the Magellan Baade Telescope. In addition to recovering the brightest nine previously known member stars in the Tucana III core, we identify 22 members in the tidal tails.We observe strong evidence for a velocity gradient of 8.0 ± 0.4 km s-1 deg-1 over at least 3° on the sky. Based on the continuity in velocity, we confirm that the Tucana III tails are real tidal extensions of Tucana III. The large velocity gradient of the stream implies that Tucana III is likely on a radial orbit. We successfully obtain metallicities for four members in the core and 12 members in the tails. We find that members close to the ends of the stream tend to be more metal-poor than members in the core, indicating a possible metallicity gradient between the center of the progenitor halo and its edge. The spread in metallicity suggests that the progenitor of the Tucana III stream is likely a dwarf galaxy rather than a star cluster. Furthermore, we find that with the precise photometry of the Dark Energy Survey data, there is a discernible color offset between metal-rich disk stars and metal-poor stream members. This metallicity-dependent color offers a more efficient method to recognize metal-poor targets and will increase the selection efficiency of stream members for future spectroscopic follow-up programs on stellar streams.

KW - Local Group

KW - dark matter

KW - galaxies: dwarf

KW - galaxies: individual (Tucana III)

KW - stars: abundances

UR - http://www.scopus.com/inward/record.url?scp=85055315576&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85055315576&partnerID=8YFLogxK

U2 - 10.3847/1538-4357/aadf91

DO - 10.3847/1538-4357/aadf91

M3 - Article

AN - SCOPUS:85055315576

SN - 0004-637X

VL - 866

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1

M1 - 22

ER -

The First Tidally Disrupted Ultra-faint Dwarf Galaxy? A Spectroscopic Analysis of the Tucana III Stream

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The First Tidally Disrupted Ultra-faint Dwarf Galaxy? A Spectroscopic Analysis of the Tucana III Stream

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Spectroscopic analysis of Tuc III stream

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