Internal kinematics of the Andromeda II dwarf spheroidal galaxy

Patrick Côté, Mario Mateo, Edward W. Olszewski, K. H. Cook

Research output: Contribution to journalArticle

40 Scopus citations

Abstract

The High-Resolution Echelle Spectrometer on the Keck I telescope has been used to measure nine radial velocities having a median precision of ≃2 km s-1 for seven red giants belonging to the isolated dwarf spheroidal galaxy Andromeda II (And II). We find a weighted mean radial velocity of v̄r = -188 ± 3 km s-1 and a central velocity dispersion of σ0 = 9.3+2.7-2.6 km s-1. There may be evidence for a radial velocity gradient across the face of the galaxy, although the significance of this result is low because of the small number of stars having measured velocities. Our best estimate for the global mass-to-light ratio of And II is M/Lv = 20.9+13.9-10.1 M ⊙/Lv, ⊙. This value is similar to those of several Galactic dwarf spheroidal galaxies and is consistent with the presence of a massive dark halo in And II.

Original languageEnglish (US)
Pages (from-to)147-151
Number of pages5
JournalAstrophysical Journal
Volume526
Issue number1 PART 1
StatePublished - Nov 20 1999

Keywords

  • Galaxies: Individual (Andromeda II)
  • Galaxies: dwarf
  • Galaxies: kinematics and dynamics

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Côté, P., Mateo, M., Olszewski, E. W., & Cook, K. H. (1999). Internal kinematics of the Andromeda II dwarf spheroidal galaxy. Astrophysical Journal, 526(1 PART 1), 147-151.