Velocity dispersion profiles of seven dwarf spheroidal galaxies

Matthew G. Walker, Mario Mateo, Edward W Olszewski, Oleg Y. Gnedin, Xiao Wang, Bodhisattva Sen, Michael Woodroofe

Research output: Contribution to journalArticle

193 Citations (Scopus)

Abstract

We present stellar velocity dispersion profiles for seven Milky Way dwarf spheroidal (dSph) satellite galaxies. We have measured 8394 line-of-sight velocities (±2.5 km s-1) for 6804 stars from high-resolution spectra obtained at the Magellan and MMT telescopes. We combine these new data with previously published velocities to obtain the largest available kinematic samples, which include more than 5500 dSph members. All the measured dSphs have stellar velocity dispersion of order 10 km s-1 that remains approximately constant with distance from the dSph center, out to and in some cases beyond the radius at which the mean surface brightness falls to the background level. Assuming dSphs reside within dark matter halos characterized by the NFW density profile, we obtain reasonable fits to the empirical velocity dispersion profiles. These fits imply that, among the seven dSphs, Mvir ∼108-109 M. The mass enclosed at a radius of 600 pc, the region common to all data sets, lies in the range (2- 7) × 107 M.

Original languageEnglish (US)
JournalAstrophysical Journal
Volume667
Issue number1
StatePublished - Sep 20 2007

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dwarf galaxies
profiles
radii
background level
line of sight
halos
dark matter
brightness
kinematics
telescopes
galaxies
stars
high resolution

Keywords

  • Dark matter
  • Galaxies: dwarf
  • Galaxies: kinematics and dynamics
  • Local Group
  • Techniques: radial velocities

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Walker, M. G., Mateo, M., Olszewski, E. W., Gnedin, O. Y., Wang, X., Sen, B., & Woodroofe, M. (2007). Velocity dispersion profiles of seven dwarf spheroidal galaxies. Astrophysical Journal, 667(1).

Velocity dispersion profiles of seven dwarf spheroidal galaxies. / Walker, Matthew G.; Mateo, Mario; Olszewski, Edward W; Gnedin, Oleg Y.; Wang, Xiao; Sen, Bodhisattva; Woodroofe, Michael.

In: Astrophysical Journal, Vol. 667, No. 1, 20.09.2007.

Research output: Contribution to journalArticle

Walker, MG, Mateo, M, Olszewski, EW, Gnedin, OY, Wang, X, Sen, B & Woodroofe, M 2007, 'Velocity dispersion profiles of seven dwarf spheroidal galaxies', Astrophysical Journal, vol. 667, no. 1.
Walker MG, Mateo M, Olszewski EW, Gnedin OY, Wang X, Sen B et al. Velocity dispersion profiles of seven dwarf spheroidal galaxies. Astrophysical Journal. 2007 Sep 20;667(1).
Walker, Matthew G. ; Mateo, Mario ; Olszewski, Edward W ; Gnedin, Oleg Y. ; Wang, Xiao ; Sen, Bodhisattva ; Woodroofe, Michael. / Velocity dispersion profiles of seven dwarf spheroidal galaxies. In: Astrophysical Journal. 2007 ; Vol. 667, No. 1.
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