On kinematic substructure in the Sextans dwarf spheroidal galaxy

被引：64

作者：

Walker, MG

Mateo, M

Olszewski, EW

Pal, JK

Sen, B

Woodroofe, M

机构：

[1] Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA

[2] Univ Arizona, Steward Observ, Tucson, AZ 85721 USA

[3] Univ Michigan, Dept Stat, Ann Arbor, MI 48109 USA

来源：

ASTROPHYSICAL JOURNAL | 2006年 / 642卷 / 01期

关键词：

galaxies : dwarf; galaxies : individual (Sextans); galaxies : kinematics and dynamics; Local Group;

D O I：

10.1086/504522

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We present multifiber echelle radial velocity results for 551 stars in the Sextans dwarf spheroidal galaxy and identify 294 stars as probable Sextans members. The projected velocity dispersion profile of the binned data remains flat to a maximum angular radius of 30'. We introduce a nonparametric technique for estimating the projected velocity dispersion surface and use this to search for kinematic substructure. Our data do not confirm previous reports of a kinematically distinct stellar population at the Sextans center. Instead we detect a region near the Sextans core radius that is kinematically colder than the overall Sextans sample with 95% confidence.

引用

收藏

页码：L41 / L44

页数：4

相关论文

共 21 条

[1] MEASURES OF LOCATION AND SCALE FOR VELOCITIES IN CLUSTERS OF GALAXIES - A ROBUST APPROACH [J].

BEERS, TC ;

FLYNN, K ;

GEBHARDT, K .

ASTRONOMICAL JOURNAL, 1990, 100 (01) :32-46

[2] MIKE: A double echelle spectrograph for the Magellan Telescopes at Las Campanas Observatory. [J].

Bernstein, RA ;

Shectman, SA ;

Gunnels, S ;

Mochnacki, S ;

Athey, A .

INSTRUMENT DESIGN AND PERFORMANCE FOR OPTICAL/INFRARED GROUND-BASED TELESCOPES, PTS 1-3, 2003, 4841 :1694-1704

[3] Shell structure in the Fornax dwarf spheroidal galaxy [J].

Coleman, M ;

Da Costa, GS ;

Bland-Hawthorn, J ;

Martínez-Delgado, D ;

Freeman, KC ;

Malin, D .

ASTRONOMICAL JOURNAL, 2004, 127 (02) :832-839

[4] A wide-field survey of the Fornax dwarf spheroidal galaxy [J].

Coleman, MG ;

Da Costa, GS ;

Bland-Hawthorn, J ;

Freeman, KC .

ASTRONOMICAL JOURNAL, 2005, 129 (03) :1443-1464

[5]

GOERTDT T, 2006, IN PRESS MNRAS

[6] Structural parameters for the Galactic dwarf spheroidals [J].

Irwin, M ;

Hatzidimitriou, D .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1995, 277 (04) :1354-1378

[7] A photometrically and kinematically distinct core in the Sextans dwarf spheroidal galaxy [J].

Kleyna, JT ;

Wilkinson, MI ;

Evans, NW ;

Gilmore, G .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2004, 354 (04) :L66-L72

[8]

Kleyna JT, 2003, ASTROPHYS J, V588, pL21, DOI 10.1086/375522

[9] Dwarf galaxies of the local group [J].

Mateo, M .

ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS, 1998, 36 :435-506

[10] Exploring halo substructure with giant stars:: The velocity dispersion profiles of the ursa minor and Draco dwarf spheroidal galaxies at large angular separations [J].

Muñoz, RR ;

Frinchaboy, PM ;

Majewski, SR ;

Kuhn, JR ;

Chou, MY ;

Palma, C ;

Sohn, ST ;

Patterson, RJ ;

Siegel, MH .

ASTROPHYSICAL JOURNAL, 2005, 631 (02) :L137-L141