TY - JOUR
T1 - A Multi-epoch Kinematic Study of the Remote Dwarf Spheroidal Galaxy Leo II
AU - Spencer, Meghin E.
AU - Mateo, Mario
AU - Walker, Matthew G.
AU - Olszewski, Edward W.
N1 - Funding Information:
M.E.S. is supported by the National Science Foundation Graduate Research Fellowship under grant number DGE 1256260. M.M. acknowledges support from NSF grant AST1312997. M.W. acknowledges support from NSF grants AST1313045 and AST1412999. E.O. acknowledges support from NSF grant AST1313006.
Publisher Copyright:
© 2017. The American Astronomical Society. All rights reserved.
PY - 2017/2/20
Y1 - 2017/2/20
N2 - 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.
AB - 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.
KW - galaxies: abundances
KW - galaxies: dwarf
KW - galaxies: individual (Leo II)
KW - galaxies: kinematics and dynamics
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U2 - 10.3847/1538-4357/836/2/202
DO - 10.3847/1538-4357/836/2/202
M3 - Article
AN - SCOPUS:85014360768
VL - 836
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 202
ER -