ACCURATE STELLAR KINEMATICS AT FAINT MAGNITUDES: APPLICATION TO THE BOOTES I DWARF SPHEROIDAL GALAXY

被引：168

作者：

Koposov, Sergey E. ^{[1
,2
]}

Gilmore, G. ^{[1
]}

Walker, M. G. ^{[1
,3
]}

Belokurov, V. ^{[1
]}

Evans, N. Wyn ^{[1
]}

Fellhauer, M. ^{[4
]}

Gieren, W. ^{[4
]}

Geisler, D. ^{[4
]}

Monaco, L. ^{[4
,5
]}

Norris, J. E. ^{[6
]}

Okamoto, S. ^{[1
]}

Penarrubia, J. ^{[1
]}

Wilkinson, M. ^{[7
]}

Wyse, R. F. G. ^{[8
]}

Zucker, D. B. ^{[9
,10
]}

机构：

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

[2] Moscow MV Lomonosov State Univ, Sternberg Astron Inst, Moscow 119992, Russia

[3] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA

[4] Univ Concepcion, Dept Astron, Concepcion, Chile

[5] European So Observ, Santiago 19, Chile

[6] Australian Natl Univ, Mt Stromlo Observ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia

[7] Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England

[8] Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA

[9] Macquarie Univ, Dept Phys & Astron, N Ryde, NSW 2109, Australia

[10] Australian Astron Observ, Epping, NSW 1710, Australia

来源：

ASTROPHYSICAL JOURNAL | 2011年 / 736卷 / 02期

关键词：

galaxies: dwarf; galaxies: individual (Bootes I); galaxies: kinematics and dynamics; methods: data analysis; techniques: radial velocities; MILKY-WAY SATELLITE; SIGHT VELOCITY DISTRIBUTIONS; ABSORPTION-LINE SPECTRA; DIGITAL SKY SURVEY; DARK-MATTER; LUMINOSITY FUNCTION; GIANT STARS; DISPERSION; POPULATION; METALLICITY;

D O I：

10.1088/0004-637X/736/2/146

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We develop, implement, and characterize an enhanced data reduction approach which delivers precise, accurate, radial velocities from moderate resolution spectroscopy with the fiber-fed VLT/FLAMES+GIRAFFE facility. This facility, with appropriate care, delivers radial velocities adequate to resolve the intrinsic velocity dispersions of the very faint dwarf spheroidal (dSph) galaxies. Importantly, repeated measurements let us reliably calibrate our individual velocity errors (0.2 km s(-1) <= delta(V) <= 5 km s(-1)) and directly detect stars with variable radial velocities. We show, by application to the Bootes I dSph, that the intrinsic velocity dispersion of this system is significantly below 6.5 km s(-1) reported by previous studies. Our data favor a two-population model of Bootes I, consisting of a majority "cold" stellar component, with velocity dispersion 2.4(-0.5)(+0.9) km s(-1), and a minority "hot" stellar component, with velocity dispersion similar to 9 km s(-1), although we cannot completely rule out a single component distribution with velocity dispersion 4.6(-0.6)(0.8) km s(-1). We speculate that this complex velocity distribution actually reflects the distribution of velocity anisotropy in Bootes I, which is a measure of its formation processes.

引用

页数：17

共 85 条

[1]

[Anonymous], 1993, Probabilistic inference using Markov chain Monte Carlo methods

[2]

[Anonymous], 1994, Kernel smoothing

[3] The absence of HI in the Bootes dwarf spheroidal galaxy [J].

Bailin, Jeremy ;

Ford, Alyson .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2007, 375 (01) :L41-L45

[4] The photoevaporation of dwarf galaxies during reionization [J].

Barkana, R ;

Loeb, A .

ASTROPHYSICAL JOURNAL, 1999, 523 (01) :54-65

[5] The velocity dispersion and mass-to-light ratio of the remote halo globular cluster NGC 2419 [J].

Baumgardt, H. ;

Cote, P. ;

Hilker, M. ;

Rejkuba, M. ;

Mieske, S. ;

Djorgovski, S. G. ;

Stetson, Peter .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2009, 396 (04) :2051-2060

[6] LEO V: A COMPANION OF A COMPANION OF THE MILKY WAY GALAXY? [J].

Belokurov, V. ;

Walker, M. G. ;

Evans, N. W. ;

Faria, D. C. ;

Gilmore, G. ;

Irwin, M. J. ;

Koposov, S. ;

Mateo, M. ;

Olszewski, E. ;

Zucker, D. B. .

ASTROPHYSICAL JOURNAL LETTERS, 2008, 686 (02) :L83-L86

[7] Cats and dogs, hair and a hero: A quintet of new Milky Way companions [J].

Belokurov, V. ;

Zucker, D. B. ;

Evans, N. W. ;

Kleyna, J. T. ;

Koposov, S. ;

Hodgkin, S. T. ;

Irwin, M. J. ;

Gilmore, G. ;

Wilkinson, M. I. ;

Fellhauer, M. ;

Bramich, D. M. ;

Hewett, P. C. ;

Vidrih, S. ;

De Jong, J. T. A. ;

Smith, J. A. ;

Rix, H. -W. ;

Bell, E. F. ;

Wyse, R. F. G. ;

Newberg, H. J. ;

Mayeur, P. A. ;

Yanny, B. ;

Rockosi, C. M. ;

Gnedin, O. Y. ;

Schneider, D. P. ;

Beers, T. C. ;

Barentine, J. C. ;

Brewington, H. ;

Brinkmann, J. ;

Harvanek, M. ;

Kleinman, S. J. ;

Krzesinski, J. ;

Long, D. ;

Nitta, A. ;

Snedden, S. A. .

ASTROPHYSICAL JOURNAL, 2007, 654 (02) :897-906

[8] A faint new milky way satellite in Bootes [J].

Belokurov, V. ;

Zucker, D. B. ;

Evans, N. W. ;

Wilkinson, M. I. ;

Irwin, M. J. ;

Hodgkin, S. ;

Bramich, D. M. ;

Irwin, J. M. ;

Gilmore, G. ;

Willman, B. ;

Vidrih, S. ;

Newberg, H. J. ;

Wyse, R. F. G. ;

Fellhauer, M. ;

Hewett, P. C. ;

Cole, N. ;

Bell, E. F. ;

Beers, T. C. ;

Rockosi, C. M. ;

Yanny, B. ;

Grebel, E. K. ;

Schneider, D. P. ;

Lupton, R. ;

Barentine, J. C. ;

Brewington, H. ;

Brinkmann, J. ;

Harvanek, M. ;

Kleinman, S. J. ;

Krzesinski, J. ;

Long, D. ;

Nitta, A. ;

Smith, J. A. ;

Snedden, S. A. .

ASTROPHYSICAL JOURNAL, 2006, 647 (02) :L111-L114

[9] The discovery of Segue 2: a prototype of the population of satellites of satellites [J].

Belokurov, V. ;

Walker, M. G. ;

Evans, N. W. ;

Gilmore, G. ;

Irwin, M. J. ;

Mateo, M. ;

Mayer, L. ;

Olszewski, E. ;

Bechtold, J. ;

Pickering, T. .

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 2009, 397 (04) :1748-1755

[10] What shapes the luminosity function of galaxies? [J].

Benson, AJ ;

Bower, RG ;

Frenk, CS ;

Lacey, CG ;

Baugh, CM ;

Cole, S .

ASTROPHYSICAL JOURNAL, 2003, 599 (01) :38-49

← 1 2 3 4 5 6 7 8 9 →