Discovery of an unusual dwarf galaxy in the outskirts of the milky way

M. J. Irwin; V. Belokurov; N. W. Evans; E. V. Ryan-Weber; J. T A De Jong; S. Koposov; D. B. Zucker; S. T. Hodgkin; G. Gilmore; P. Prema; L. Hebb; A. Begum; M. Fellhauer; P. C. Hewett; R. C. Kennicutt; M. I. Wilkinson; D. M. Bramich; S. Vidrih; H. W. Rix; T. C. Beers; J. C. Barentine; H. Brewington; M. Harvanek; J. Krzesinski; D. Long; A. Nitta; S. A. Snedden

doi:10.1086/512183

Discovery of an unusual dwarf galaxy in the outskirts of the milky way

M. J. Irwin^*, V. Belokurov, N. W. Evans, E. V. Ryan-Weber, J. T A De Jong, S. Koposov, D. B. Zucker, S. T. Hodgkin, G. Gilmore, P. Prema, L. Hebb, A. Begum, M. Fellhauer, P. C. Hewett, R. C. Kennicutt, M. I. Wilkinson, D. M. Bramich, S. Vidrih, H. W. Rix, T. C. BeersJ. C. Barentine, H. Brewington, M. Harvanek, J. Krzesinski, D. Long, A. Nitta, S. A. Snedden

^*Corresponding author for this work

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

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Abstract

We announce the discovery of a new dwarf galaxy, Leo T, in the Local Group. It was found as a stellar overdensity in the Sloan Digital Sky Survey Data Release 5 (SDSS DR5). The color-magnitude diagram of Leo T shows two well-defined features, which we interpret as a red giant branch and a sequence of young, massive stars. As judged from fits to the color-magnitude diagram, it lies at a distance of ∼420 kpc and has an intermediate-age stellar population with a metallicity of [Fe/H] = -1.6, together with a young population of blue stars of age ∼200 Myr. There is a compact cloud of neutral hydrogen with mass ∼10⁵ M_⊙ and radial velocity +35 km s^-1 coincident with the object visible in the HIPASS channel maps. Leo T is the smallest, lowest luminosity galaxy found to date with recent star formation. It appears to be a transition object similar to, but much lower luminosity than, the Phoenix dwarf.

Original language	English
Pages (from-to)	L13-L16
Number of pages	4
Journal	Astrophysical Journal
Volume	656
Issue number	1
DOIs	https://doi.org/10.1086/512183
Publication status	Published - 10 Feb 2007
Externally published	Yes

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Irwin, M. J., Belokurov, V., Evans, N. W., Ryan-Weber, E. V., De Jong, J. T. A., Koposov, S., Zucker, D. B., Hodgkin, S. T., Gilmore, G., Prema, P., Hebb, L., Begum, A., Fellhauer, M., Hewett, P. C., Kennicutt, R. C., Wilkinson, M. I., Bramich, D. M., Vidrih, S., Rix, H. W., ... Snedden, S. A. (2007). Discovery of an unusual dwarf galaxy in the outskirts of the milky way. Astrophysical Journal, 656(1), L13-L16. https://doi.org/10.1086/512183

@article{481d5755f89e46f784c8a093ea114b09,

title = "Discovery of an unusual dwarf galaxy in the outskirts of the milky way",

abstract = "We announce the discovery of a new dwarf galaxy, Leo T, in the Local Group. It was found as a stellar overdensity in the Sloan Digital Sky Survey Data Release 5 (SDSS DR5). The color-magnitude diagram of Leo T shows two well-defined features, which we interpret as a red giant branch and a sequence of young, massive stars. As judged from fits to the color-magnitude diagram, it lies at a distance of ∼420 kpc and has an intermediate-age stellar population with a metallicity of [Fe/H] = -1.6, together with a young population of blue stars of age ∼200 Myr. There is a compact cloud of neutral hydrogen with mass ∼105 M⊙ and radial velocity +35 km s-1 coincident with the object visible in the HIPASS channel maps. Leo T is the smallest, lowest luminosity galaxy found to date with recent star formation. It appears to be a transition object similar to, but much lower luminosity than, the Phoenix dwarf.",

author = "Irwin, {M. J.} and V. Belokurov and Evans, {N. W.} and Ryan-Weber, {E. V.} and {De Jong}, {J. T A} and S. Koposov and Zucker, {D. B.} and Hodgkin, {S. T.} and G. Gilmore and P. Prema and L. Hebb and A. Begum and M. Fellhauer and Hewett, {P. C.} and Kennicutt, {R. C.} and Wilkinson, {M. I.} and Bramich, {D. M.} and S. Vidrih and Rix, {H. W.} and Beers, {T. C.} and Barentine, {J. C.} and H. Brewington and M. Harvanek and J. Krzesinski and D. Long and A. Nitta and Snedden, {S. A.}",

year = "2007",

month = feb,

day = "10",

doi = "10.1086/512183",

language = "English",

volume = "656",

pages = "L13--L16",

journal = "Astrophysical Journal",

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Irwin, MJ, Belokurov, V, Evans, NW, Ryan-Weber, EV, De Jong, JTA, Koposov, S, Zucker, DB, Hodgkin, ST, Gilmore, G, Prema, P, Hebb, L, Begum, A, Fellhauer, M, Hewett, PC, Kennicutt, RC, Wilkinson, MI, Bramich, DM, Vidrih, S, Rix, HW, Beers, TC, Barentine, JC, Brewington, H, Harvanek, M, Krzesinski, J, Long, D, Nitta, A & Snedden, SA 2007, 'Discovery of an unusual dwarf galaxy in the outskirts of the milky way', Astrophysical Journal, vol. 656, no. 1, pp. L13-L16. https://doi.org/10.1086/512183

TY - JOUR

T1 - Discovery of an unusual dwarf galaxy in the outskirts of the milky way

AU - Irwin, M. J.

AU - Belokurov, V.

AU - Evans, N. W.

AU - Ryan-Weber, E. V.

AU - De Jong, J. T A

AU - Koposov, S.

AU - Zucker, D. B.

AU - Hodgkin, S. T.

AU - Gilmore, G.

AU - Prema, P.

AU - Hebb, L.

AU - Begum, A.

AU - Fellhauer, M.

AU - Hewett, P. C.

AU - Kennicutt, R. C.

AU - Wilkinson, M. I.

AU - Bramich, D. M.

AU - Vidrih, S.

AU - Rix, H. W.

AU - Beers, T. C.

AU - Barentine, J. C.

AU - Brewington, H.

AU - Harvanek, M.

AU - Krzesinski, J.

AU - Long, D.

AU - Nitta, A.

AU - Snedden, S. A.

PY - 2007/2/10

Y1 - 2007/2/10

N2 - We announce the discovery of a new dwarf galaxy, Leo T, in the Local Group. It was found as a stellar overdensity in the Sloan Digital Sky Survey Data Release 5 (SDSS DR5). The color-magnitude diagram of Leo T shows two well-defined features, which we interpret as a red giant branch and a sequence of young, massive stars. As judged from fits to the color-magnitude diagram, it lies at a distance of ∼420 kpc and has an intermediate-age stellar population with a metallicity of [Fe/H] = -1.6, together with a young population of blue stars of age ∼200 Myr. There is a compact cloud of neutral hydrogen with mass ∼105 M⊙ and radial velocity +35 km s-1 coincident with the object visible in the HIPASS channel maps. Leo T is the smallest, lowest luminosity galaxy found to date with recent star formation. It appears to be a transition object similar to, but much lower luminosity than, the Phoenix dwarf.

AB - We announce the discovery of a new dwarf galaxy, Leo T, in the Local Group. It was found as a stellar overdensity in the Sloan Digital Sky Survey Data Release 5 (SDSS DR5). The color-magnitude diagram of Leo T shows two well-defined features, which we interpret as a red giant branch and a sequence of young, massive stars. As judged from fits to the color-magnitude diagram, it lies at a distance of ∼420 kpc and has an intermediate-age stellar population with a metallicity of [Fe/H] = -1.6, together with a young population of blue stars of age ∼200 Myr. There is a compact cloud of neutral hydrogen with mass ∼105 M⊙ and radial velocity +35 km s-1 coincident with the object visible in the HIPASS channel maps. Leo T is the smallest, lowest luminosity galaxy found to date with recent star formation. It appears to be a transition object similar to, but much lower luminosity than, the Phoenix dwarf.

UR - http://www.scopus.com/inward/record.url?scp=33847397895&partnerID=8YFLogxK

U2 - 10.1086/512183

DO - 10.1086/512183

M3 - Article

AN - SCOPUS:33847397895

SN - 0004-637X

VL - 656

SP - L13-L16

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1

ER -

Discovery of an unusual dwarf galaxy in the outskirts of the milky way

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