The origin of the bifurcation in the sagittarius stream

被引：205

作者：

Fellhauer, M.

Belokurov, V.

Evans, N. W.

Wilkinson, M. I.

Zucker, D. B.

Gilmore, G.

Irwin, M. J.

Bramich, D. M.

Vidrih, S.

Wyse, R. F. G.

Beers, T. C.

Brinkmann, J.

机构：

[1] Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England

[2] Johns Hopkins Univ, Baltimore, MD 21218 USA

[3] Michigan State Univ, Dept Phys & Astron, CSCE, E Lansing, MI 48824 USA

[4] Michigan State Univ, Joint Inst Nucl Astrophys, E Lansing, MI 48824 USA

[5] Apache Point Observ, Sunspot, NM 88349 USA

来源：

ASTROPHYSICAL JOURNAL | 2006年 / 651卷 / 01期

关键词：

galaxies : dwarf; galaxies : individual (Sgr dSph); Galaxy : halo; Galaxy : structure;

D O I：

10.1086/507128

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

The latest Sloan Digital Sky Survey data reveal a prominent bifurcation in the distribution of debris of the Sagittarius dwarf spheroidal (Sgr) beginning at a right ascension of alpha approximate to 190 degrees. Two branches of the stream (A and B) persist at roughly the same heliocentric distance over at least 50 degrees of arc. There is also evidence for a more distant structure (C) well behind the A branch. This paper provides the first explanation for the bifurcation. It is caused by the projection of the young leading (A) and old trailing (B) tidal arms of the Sgr, while the old leading arm (C) lies well behind A. This explanation is only possible if the halo is close to spherical, as the angular difference between the branches is a measure of the precession of the orbital plane.

引用

页码：167 / 173

页数：7

共 34 条

[1] The Fourth Data Release of the Sloan Digital Sky Survey [J].

Adelman-McCarthy, JK ;

Agüeros, MA ;

Allam, SS ;

Anderson, KSJ ;

Anderson, SF ;

Annis, J ;

Bahcall, NA ;

Baldry, IK ;

Barentine, JC ;

Berlind, A ;

Bernardi, M ;

Blanton, MR ;

Boroski, WN ;

Brewington, HJ ;

Brinchmann, J ;

Brinkmann, J ;

Brunner, RJ ;

Budavári, T ;

Carey, LN ;

Carr, MA ;

Castander, FJ ;

Connolly, AJ ;

Csabai, I ;

Czarapata, PC ;

Dalcanton, JJ ;

Doi, M ;

Dong, F ;

Eisenstein, DJ ;

Evans, ML ;

Fan, XH ;

Finkbeiner, DP ;

Friedman, SD ;

Frieman, JA ;

Fukugita, M ;

Gillespie, B ;

Glazebrook, K ;

Gray, J ;

Grebel, EK ;

Gunn, JE ;

Gurbani, VK ;

de Haas, E ;

Hall, PB ;

Harris, FH ;

Harvanek, M ;

Hawley, SL ;

Hayes, J ;

Hendry, JS ;

Hennessy, GS ;

Hindsley, RB ;

Hirata, CM .

ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 2006, 162 (01) :38-48

[2] Mass models of the Milky Way [J].

Dehnen, W ;

Binney, J .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1998, 294 (03) :429-438

[3] Absolute proper motion of the Sagittarius dwarf galaxy and of the outer regions of the Milky Way bulge [J].

Dinescu, DI ;

Girard, TM ;

van Altena, WF ;

López, CE .

ASTROPHYSICAL JOURNAL, 2005, 618 (01) :L25-L28

[4] SIMPLE GALAXY MODELS WITH MASSIVE HALOES [J].

EVANS, NW .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1993, 260 (01) :191-201

[5] SUPERBOX - an efficient code for collisionless galactic dynamics [J].

Fellhauer, M ;

Kroupa, P ;

Baumgardt, H ;

Bien, R ;

Boily, CM ;

Spurzem, R ;

Wassmer, N .

NEW ASTRONOMY, 2000, 5 (06) :305-326

[6]

GREBEL EK, 2000, BAAS, V32, P698

[7] The 2.5 m telescope of the Sloan Digital Sky Survey [J].

Gunn, JE ;

Siegmund, WA ;

Mannery, EJ ;

Owen, RE ;

Hull, CL ;

Leger, RF ;

Carey, LN ;

Knapp, GR ;

York, DG ;

Boroski, WN ;

Kent, SM ;

Lupton, RH ;

Rockosi, CM ;

Evans, ML ;

Waddell, P ;

Anderson, JE ;

Annis, J ;

Barentine, JC ;

Bartoszek, LM ;

Bastian, S ;

Bracker, SB ;

Brewington, HJ ;

Briegel, CI ;

Brinkmann, J ;

Brown, YJ ;

Carr, MA ;

Czarapata, PC ;

Drennan, CC ;

Dombeck, T ;

Federwitz, GR ;

Gillespie, BA ;

Gonzales, C ;

Hansen, SU ;

Harvanek, M ;

Hayes, J ;

Jordan, W ;

Kinney, E ;

Klaene, M ;

Kleinman, SJ ;

Kron, RG ;

Kresinski, J ;

Lee, G ;

Limmongkol, S ;

Lindenmeyer, CW ;

Long, DC ;

Loomis, CL ;

McGehee, PM ;

Mantsch, PM ;

Neilsen, EH ;

Neswold, RM .

ASTRONOMICAL JOURNAL, 2006, 131 (04) :2332-2359

[8] Is the dark halo of our Galaxy spherical? [J].

Helmi, A .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2004, 351 (02) :643-648

[9] Velocity trends in the debris of sagittarius and the shape of the dark matter halo of our galaxy [J].

Helmi, A .

ASTROPHYSICAL JOURNAL, 2004, 610 (02) :L97-L100

[10] A photometricity and extinction monitor at the Apache Point Observatory [J].

Hogg, DW ;

Finkbeiner, DP ;

Schlegel, DJ ;

Gunn, JE .

ASTRONOMICAL JOURNAL, 2001, 122 (04) :2129-2138

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