A Multi-epoch Kinematic Study of the Remote Dwarf Spheroidal Galaxy Leo II

Meghin E. Spencer, Mario Mateo, Matthew G. Walker, Edward W. Olszewski

Research output: Research - peer-reviewArticle

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Abstract

We conducted a large spectroscopic survey of 336 red giants in the direction of the Leo II dwarf galaxy using Hectochelle on the Multiple Mirror Telescope, and we conclude that 175 of them are members based on their radial velocities and surface gravities. Of this set, 40 stars have never before been observed spectroscopically. The systemic velocity of the dwarf is 78.3 ± 0.6 km s-1 with a velocity dispersion of 7.4 ± 0.4 km s-1. We identify one star beyond the tidal radius of Leo II but find no signatures of uniform rotation, kinematic asymmetries, or streams. The stars show a strong metallicity gradient of -1.53 ± 0.10 dex kpc-1 and have a mean metallicity of -1.70 ± 0.02 dex. There is also evidence of two different chemodynamic populations, but the signal is weak. A larger sample of stars would be necessary to verify this feature.

LanguageEnglish (US)
Article number202
JournalAstrophysical Journal
Volume836
Issue number2
DOIs
StatePublished - Feb 20 2017

Fingerprint

dwarf galaxies
kinematics
time measurement
stars
metallicity
asymmetry
gravity
radial velocity
signatures
telescopes
mirrors
gravitation
gradients
radii

Keywords

  • galaxies: abundances
  • galaxies: dwarf
  • galaxies: individual (Leo II)
  • galaxies: kinematics and dynamics

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

A Multi-epoch Kinematic Study of the Remote Dwarf Spheroidal Galaxy Leo II. / Spencer, Meghin E.; Mateo, Mario; Walker, Matthew G.; Olszewski, Edward W.

In: Astrophysical Journal, Vol. 836, No. 2, 202, 20.02.2017.

Research output: Research - peer-reviewArticle

Spencer, Meghin E. ; Mateo, Mario ; Walker, Matthew G. ; Olszewski, Edward W./ A Multi-epoch Kinematic Study of the Remote Dwarf Spheroidal Galaxy Leo II. In: Astrophysical Journal. 2017 ; Vol. 836, No. 2.
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KW - galaxies: kinematics and dynamics

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