The Hercules-Aquila cloud

被引:143
作者
Belokurov, V.
Evans, N. W.
Bell, E. F.
Irwin, M. J.
Hewett, P. C.
Koposov, S.
Rockosi, C. M.
Gilmore, G.
Zucker, D. B.
Fellhauer, M.
Wilkinson, M. I.
Bramich, D. M.
Vidrih, S.
Rix, H. -W.
Beers, T. C.
Schneider, D. P.
Barentine, J. C.
Brewington, H.
Brinkmann, J.
Harvanek, M.
Krzesinski, J.
Long, D.
Pan, K.
Snedden, S. A.
Malanushenko, O.
Malanushenko, V.
机构
[1] Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England
[2] Max Planck Inst Astron, D-69117 Heidelberg, Germany
[3] Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA
[4] Michigan State Univ, Ctr Study Cosm Evolut, Dept Phys & Astron, E Lansing, MI 48824 USA
[5] Michigan State Univ, Joint Inst Nucl Astrophys, E Lansing, MI 48824 USA
[6] Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA
[7] Apache Point Observ, Sunspot, NM USA
关键词
galaxies : kinematics and dynamics; galaxies : structure; Galaxy : halo; Local Group;
D O I
10.1086/513144
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present evidence for a substantial overdensity of stars in the direction of the constellations of Hercules and Aquila. The cloud is centered at a Galactic longitude of l approximate to 40 degrees and extends above and below the Galactic plane by at least 50 degrees. Given its off-centeredness and height, it is unlikely that the Hercules-Aquila cloud is related to the bulge or thick disk. More likely, this is a new structural component of the Galaxy that passes through the disk. The cloud stretches similar to 80 degrees in longitude. Its heliocentric distance lies between 10 and 20 kpc so that the extent of the cloud in projection is similar to 20 kpc by similar to 15 kpc. It has an absolute magnitude of M-nu = -13, and its stellar population appears to be comparable to, but somewhat more metal-rich than, M92.
引用
收藏
页码:L89 / L92
页数:4
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