Discovery of an unusual dwarf galaxy in the outskirts of the Milky Way

被引：221
|
作者：
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., Jr.
Wilkinson, M. I.
Bramich, D. M.
Vidrih, S.
Rix, H. -W.
Beers, T. C.
Barentine, J. C.
Brewington, H.
Harvanek, M.
Krzesinski, J.
Long, D.
Nitta, A.
Snedden, S. A.
机构：
[1] Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England
[2] Max Planck Inst Astron, D-69117 Heidelberg, Germany
[3] Univ St Andrews, Sch Phys & Astron, N Haug, Scotland
[4] Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA
[5] Apache Point Observ, Sunspot, NM USA
[6] Cracow Pedag Univ, Mt Suhora Observ, Krakow, Poland
[7] Gemini Observ, Hilo, HI USA
来源：
ASTROPHYSICAL JOURNAL | 2007年 / 656卷 / 01期
关键词：
galaxies : dwarf; galaxies : individual (Leo); Local Group;
D O I：
10.1086/512183
中图分类号：
P1 [天文学];
学科分类号：
0704 ;
摘要：
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 similar to 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 similar to 200 Myr. There is a compact cloud of neutral hydrogen with mass similar to 10(5) 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.
引用
收藏
页码：L13 / L16
页数：4
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