STELLAR KINEMATICS AND METALLICITIES IN THE ULTRA-FAINT DWARF GALAXY RETICULUM II

J. D. Simon; A. Drlica-Wagner; T. S. Li; B. Nord; M. Geha; K. Bechtol; E. Balbinot; E. Buckley-Geer; H. Lin; J. Marshall; B. Santiago; L. Strigari; M. Wang; R. H. Wechsler; B. Yanny; T. Abbott; A. H. Bauer; G. M. Bernstein; E. Bertin; D. Brooks; D. L. Burke; D. Capozzi; A. Carnero Rosell; M. Carrasco Kind; C. B. D'Andrea; L. N. Da Costa; D. L. DePoy; S. Desai; H. T. Diehl; S. Dodelson; C. E. Cunha; J. Estrada; A. E. Evrard; A. Fausti Neto; E. Fernandez; D. A. Finley; B. Flaugher; J. Frieman; E. Gaztanaga; D. Gerdes; D. Gruen; R. A. Gruendl; K. Honscheid; D. James; S. Kent; K. Kuehn; N. Kuropatkin; O. Lahav; M. A.G. Maia; M. March; P. Martini; C. J. Miller; R. Miquel; R. Ogando; A. K. Romer; A. Roodman; E. S. Rykoff; M. Sako; E. Sanchez; M. Schubnell; I. Sevilla; R. C. Smith; M. Soares-Santos; F. Sobreira; E. Suchyta; M. E.C. Swanson; G. Tarle; J. Thaler; D. Tucker; V. Vikram; A. R. Walker; W. Wester

doi:10.1088/0004-637X/808/1/95

STELLAR KINEMATICS AND METALLICITIES IN THE ULTRA-FAINT DWARF GALAXY RETICULUM II

J. D. Simon, A. Drlica-Wagner, T. S. Li, B. Nord, M. Geha, K. Bechtol, E. Balbinot, E. Buckley-Geer, H. Lin, J. Marshall, B. Santiago, L. Strigari, M. Wang, R. H. Wechsler, B. Yanny, T. Abbott, A. H. Bauer, G. M. Bernstein, E. Bertin, D. BrooksD. L. Burke, D. Capozzi, A. Carnero Rosell, M. Carrasco Kind, C. B. D'Andrea, L. N. Da Costa, D. L. DePoy, S. Desai, H. T. Diehl, S. Dodelson, C. E. Cunha, J. Estrada, A. E. Evrard, A. Fausti Neto, E. Fernandez, D. A. Finley, B. Flaugher, J. Frieman, E. Gaztanaga, D. Gerdes, D. Gruen, R. A. Gruendl, K. Honscheid, D. James, S. Kent, K. Kuehn, N. Kuropatkin, O. Lahav, M. A.G. Maia, M. March, P. Martini, C. J. Miller, R. Miquel, R. Ogando, A. K. Romer, A. Roodman, E. S. Rykoff, M. Sako, E. Sanchez, M. Schubnell, I. Sevilla, R. C. Smith, M. Soares-Santos, F. Sobreira, E. Suchyta, M. E.C. Swanson, G. Tarle, J. Thaler, D. Tucker, V. Vikram, A. R. Walker, W. Wester

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© 2015. The American Astronomical Society. All rights reserved. We present Magellan/M2FS, Very Large Telescope/GIRAFFE, and Gemini South/GMOS spectroscopy of the newly discovered Milky Way satellite Reticulum II. Based on the spectra of 25 Ret II member stars selected from Dark Energy Survey imaging, we measure a mean heliocentric velocity of 62.8 ± 0.5 km s-1 and a velocity dispersion of 3.3 ± 0.7 km s-1. The mass-to-light ratio of Ret II within its half-light radius is 470 ± 210 M⊙/L⊙, demonstrating that it is a strongly dark matter-dominated system. Despite its spatial proximity to the Magellanic Clouds, the radial velocity of Ret II differs from that of the LMC and SMC by 199 and 83 km s-1, respectively, suggesting that it is not gravitationally bound to the Magellanic system. The likely member stars of Ret II span 1.3 dex in metallicity, with a dispersion of 0.28 ± 0.09 dex, and we identify several extremely metal-poor stars with [Fe/H] < -3. In combination with its luminosity, size, and ellipticity, these results confirm that Ret II is an ultra-faint dwarf galaxy. With a mean metallicity of [Fe/H] = -2.65 ± 0.07, Ret II matches Segue 1 as the most metal-poor galaxy known. Although Ret II is the third-closest dwarf galaxy to the Milky Way, the line-of-sight integral of the dark matter density squared is log10(J) = 18.8 ± 0.6 GeV2 cm-5 within 0°.2, indicating that the predicted gamma-ray flux from dark matter annihilation in Ret II is lower than that of several other dwarf galaxies.

Idioma original	Anglès
Número d’article	95
Revista	Astrophysical Journal
Volum	808
Número	1
DOIs	https://doi.org/10.1088/0004-637X/808/1/95
Estat de la publicació	Publicada - 20 de jul. 2015

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Simon, J. D., Drlica-Wagner, A., Li, T. S., Nord, B., Geha, M., Bechtol, K., Balbinot, E., Buckley-Geer, E., Lin, H., Marshall, J., Santiago, B., Strigari, L., Wang, M., Wechsler, R. H., Yanny, B., Abbott, T., Bauer, A. H., Bernstein, G. M., Bertin, E., ... Wester, W. (2015). STELLAR KINEMATICS AND METALLICITIES IN THE ULTRA-FAINT DWARF GALAXY RETICULUM II. Astrophysical Journal, 808(1), Article 95. https://doi.org/10.1088/0004-637X/808/1/95

@article{dd7da69d7edb4eacb98366b696209c13,

title = "STELLAR KINEMATICS AND METALLICITIES IN THE ULTRA-FAINT DWARF GALAXY RETICULUM II",

abstract = "{\textcopyright} 2015. The American Astronomical Society. All rights reserved. We present Magellan/M2FS, Very Large Telescope/GIRAFFE, and Gemini South/GMOS spectroscopy of the newly discovered Milky Way satellite Reticulum II. Based on the spectra of 25 Ret II member stars selected from Dark Energy Survey imaging, we measure a mean heliocentric velocity of 62.8 ± 0.5 km s-1 and a velocity dispersion of 3.3 ± 0.7 km s-1. The mass-to-light ratio of Ret II within its half-light radius is 470 ± 210 M⊙/L⊙, demonstrating that it is a strongly dark matter-dominated system. Despite its spatial proximity to the Magellanic Clouds, the radial velocity of Ret II differs from that of the LMC and SMC by 199 and 83 km s-1, respectively, suggesting that it is not gravitationally bound to the Magellanic system. The likely member stars of Ret II span 1.3 dex in metallicity, with a dispersion of 0.28 ± 0.09 dex, and we identify several extremely metal-poor stars with [Fe/H] < -3. In combination with its luminosity, size, and ellipticity, these results confirm that Ret II is an ultra-faint dwarf galaxy. With a mean metallicity of [Fe/H] = -2.65 ± 0.07, Ret II matches Segue 1 as the most metal-poor galaxy known. Although Ret II is the third-closest dwarf galaxy to the Milky Way, the line-of-sight integral of the dark matter density squared is log10(J) = 18.8 ± 0.6 GeV2 cm-5 within 0°.2, indicating that the predicted gamma-ray flux from dark matter annihilation in Ret II is lower than that of several other dwarf galaxies.",

keywords = "dark matter, galaxies: dwarf, galaxies: individual (Reticulum II), galaxies: stellar content, Local Group, stars: bundances",

author = "Simon, \{J. D.\} and A. Drlica-Wagner and Li, \{T. S.\} and B. Nord and M. Geha and K. Bechtol and E. Balbinot and E. Buckley-Geer and H. Lin and J. Marshall and B. Santiago and L. Strigari and M. Wang and Wechsler, \{R. H.\} and B. Yanny and T. Abbott and Bauer, \{A. H.\} and Bernstein, \{G. M.\} and E. Bertin and D. Brooks and Burke, \{D. L.\} and D. Capozzi and Rosell, \{A. Carnero\} and Kind, \{M. Carrasco\} and D'Andrea, \{C. B.\} and \{Da Costa\}, \{L. N.\} and DePoy, \{D. L.\} and S. Desai and Diehl, \{H. T.\} and S. Dodelson and Cunha, \{C. E.\} and J. Estrada and Evrard, \{A. E.\} and Neto, \{A. Fausti\} and E. Fernandez and Finley, \{D. A.\} and B. Flaugher and J. Frieman and E. Gaztanaga and D. Gerdes and D. Gruen and Gruendl, \{R. A.\} and K. Honscheid and D. James and S. Kent and K. Kuehn and N. Kuropatkin and O. Lahav and Maia, \{M. A.G.\} and M. March and P. Martini and Miller, \{C. J.\} and R. Miquel and R. Ogando and Romer, \{A. K.\} and A. Roodman and Rykoff, \{E. S.\} and M. Sako and E. Sanchez and M. Schubnell and I. Sevilla and Smith, \{R. C.\} and M. Soares-Santos and F. Sobreira and E. Suchyta and Swanson, \{M. E.C.\} and G. Tarle and J. Thaler and D. Tucker and V. Vikram and Walker, \{A. R.\} and W. Wester",

year = "2015",

month = jul,

day = "20",

doi = "10.1088/0004-637X/808/1/95",

language = "English",

volume = "808",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "1",

}

Simon, JD, Drlica-Wagner, A, Li, TS, Nord, B, Geha, M, Bechtol, K, Balbinot, E, Buckley-Geer, E, Lin, H, Marshall, J, Santiago, B, Strigari, L, Wang, M, Wechsler, RH, Yanny, B, Abbott, T, Bauer, AH, Bernstein, GM, Bertin, E, Brooks, D, Burke, DL, Capozzi, D, Rosell, AC, Kind, MC, D'Andrea, CB, Da Costa, LN, DePoy, DL, Desai, S, Diehl, HT, Dodelson, S, Cunha, CE, Estrada, J, Evrard, AE, Neto, AF, Fernandez, E, Finley, DA, Flaugher, B, Frieman, J, Gaztanaga, E, Gerdes, D, Gruen, D, Gruendl, RA, Honscheid, K, James, D, Kent, S, Kuehn, K, Kuropatkin, N, Lahav, O, Maia, MAG, March, M, Martini, P, Miller, CJ, Miquel, R, Ogando, R, Romer, AK, Roodman, A, Rykoff, ES, Sako, M, Sanchez, E, Schubnell, M, Sevilla, I, Smith, RC, Soares-Santos, M, Sobreira, F, Suchyta, E, Swanson, MEC, Tarle, G, Thaler, J, Tucker, D, Vikram, V, Walker, AR & Wester, W 2015, 'STELLAR KINEMATICS AND METALLICITIES IN THE ULTRA-FAINT DWARF GALAXY RETICULUM II', Astrophysical Journal, vol. 808, núm. 1, 95. https://doi.org/10.1088/0004-637X/808/1/95

TY - JOUR

T1 - STELLAR KINEMATICS AND METALLICITIES IN THE ULTRA-FAINT DWARF GALAXY RETICULUM II

AU - Simon, J. D.

AU - Drlica-Wagner, A.

AU - Li, T. S.

AU - Nord, B.

AU - Geha, M.

AU - Bechtol, K.

AU - Balbinot, E.

AU - Buckley-Geer, E.

AU - Lin, H.

AU - Marshall, J.

AU - Santiago, B.

AU - Strigari, L.

AU - Wang, M.

AU - Wechsler, R. H.

AU - Yanny, B.

AU - Abbott, T.

AU - Bauer, A. H.

AU - Bernstein, G. M.

AU - Bertin, E.

AU - Brooks, D.

AU - Burke, D. L.

AU - Capozzi, D.

AU - Rosell, A. Carnero

AU - Kind, M. Carrasco

AU - D'Andrea, C. B.

AU - Da Costa, L. N.

AU - DePoy, D. L.

AU - Desai, S.

AU - Diehl, H. T.

AU - Dodelson, S.

AU - Cunha, C. E.

AU - Estrada, J.

AU - Evrard, A. E.

AU - Neto, A. Fausti

AU - Fernandez, E.

AU - Finley, D. A.

AU - Flaugher, B.

AU - Frieman, J.

AU - Gaztanaga, E.

AU - Gerdes, D.

AU - Gruen, D.

AU - Gruendl, R. A.

AU - Honscheid, K.

AU - James, D.

AU - Kent, S.

AU - Kuehn, K.

AU - Kuropatkin, N.

AU - Lahav, O.

AU - Maia, M. A.G.

AU - March, M.

AU - Martini, P.

AU - Miller, C. J.

AU - Miquel, R.

AU - Ogando, R.

AU - Romer, A. K.

AU - Roodman, A.

AU - Rykoff, E. S.

AU - Sako, M.

AU - Sanchez, E.

AU - Schubnell, M.

AU - Sevilla, I.

AU - Smith, R. C.

AU - Soares-Santos, M.

AU - Sobreira, F.

AU - Suchyta, E.

AU - Swanson, M. E.C.

AU - Tarle, G.

AU - Thaler, J.

AU - Tucker, D.

AU - Vikram, V.

AU - Walker, A. R.

AU - Wester, W.

PY - 2015/7/20

Y1 - 2015/7/20

N2 - © 2015. The American Astronomical Society. All rights reserved. We present Magellan/M2FS, Very Large Telescope/GIRAFFE, and Gemini South/GMOS spectroscopy of the newly discovered Milky Way satellite Reticulum II. Based on the spectra of 25 Ret II member stars selected from Dark Energy Survey imaging, we measure a mean heliocentric velocity of 62.8 ± 0.5 km s-1 and a velocity dispersion of 3.3 ± 0.7 km s-1. The mass-to-light ratio of Ret II within its half-light radius is 470 ± 210 M⊙/L⊙, demonstrating that it is a strongly dark matter-dominated system. Despite its spatial proximity to the Magellanic Clouds, the radial velocity of Ret II differs from that of the LMC and SMC by 199 and 83 km s-1, respectively, suggesting that it is not gravitationally bound to the Magellanic system. The likely member stars of Ret II span 1.3 dex in metallicity, with a dispersion of 0.28 ± 0.09 dex, and we identify several extremely metal-poor stars with [Fe/H] < -3. In combination with its luminosity, size, and ellipticity, these results confirm that Ret II is an ultra-faint dwarf galaxy. With a mean metallicity of [Fe/H] = -2.65 ± 0.07, Ret II matches Segue 1 as the most metal-poor galaxy known. Although Ret II is the third-closest dwarf galaxy to the Milky Way, the line-of-sight integral of the dark matter density squared is log10(J) = 18.8 ± 0.6 GeV2 cm-5 within 0°.2, indicating that the predicted gamma-ray flux from dark matter annihilation in Ret II is lower than that of several other dwarf galaxies.

AB - © 2015. The American Astronomical Society. All rights reserved. We present Magellan/M2FS, Very Large Telescope/GIRAFFE, and Gemini South/GMOS spectroscopy of the newly discovered Milky Way satellite Reticulum II. Based on the spectra of 25 Ret II member stars selected from Dark Energy Survey imaging, we measure a mean heliocentric velocity of 62.8 ± 0.5 km s-1 and a velocity dispersion of 3.3 ± 0.7 km s-1. The mass-to-light ratio of Ret II within its half-light radius is 470 ± 210 M⊙/L⊙, demonstrating that it is a strongly dark matter-dominated system. Despite its spatial proximity to the Magellanic Clouds, the radial velocity of Ret II differs from that of the LMC and SMC by 199 and 83 km s-1, respectively, suggesting that it is not gravitationally bound to the Magellanic system. The likely member stars of Ret II span 1.3 dex in metallicity, with a dispersion of 0.28 ± 0.09 dex, and we identify several extremely metal-poor stars with [Fe/H] < -3. In combination with its luminosity, size, and ellipticity, these results confirm that Ret II is an ultra-faint dwarf galaxy. With a mean metallicity of [Fe/H] = -2.65 ± 0.07, Ret II matches Segue 1 as the most metal-poor galaxy known. Although Ret II is the third-closest dwarf galaxy to the Milky Way, the line-of-sight integral of the dark matter density squared is log10(J) = 18.8 ± 0.6 GeV2 cm-5 within 0°.2, indicating that the predicted gamma-ray flux from dark matter annihilation in Ret II is lower than that of several other dwarf galaxies.

KW - dark matter

KW - galaxies: dwarf

KW - galaxies: individual (Reticulum II)

KW - galaxies: stellar content

KW - Local Group

KW - stars: bundances

UR - https://www.scopus.com/pages/publications/84937922710

U2 - 10.1088/0004-637X/808/1/95

DO - 10.1088/0004-637X/808/1/95

M3 - Article

SN - 0004-637X

VL - 808

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1

M1 - 95

ER -

STELLAR KINEMATICS AND METALLICITIES IN THE ULTRA-FAINT DWARF GALAXY RETICULUM II

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