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

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{sup −1} with a velocity dispersion of 7.4 ± 0.4 km s{sup −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{sup −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.

Authors:
;  [1];  [2];  [3]
  1. Department of Astronomy, University of Michigan, Ann Arbor, MI (United States)
  2. McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, Pittsburgh, PA (United States)
  3. Steward Observatory, The University of Arizona, Tucson, AZ (United States)
Publication Date:
OSTI Identifier:
22663777
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 836; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; ASYMMETRY; DISPERSIONS; GALAXIES; GRAVITATION; METALLICITY; RADIAL VELOCITY; ROTATION; STARS; STREAMS; SURFACES; TELESCOPES

Citation Formats

Spencer, Meghin E., Mateo, Mario, Walker, Matthew G., and Olszewski, Edward W., E-mail: meghins@umich.edu. A Multi-epoch Kinematic Study of the Remote Dwarf Spheroidal Galaxy Leo II. United States: N. p., 2017. Web. doi:10.3847/1538-4357/836/2/202.
Spencer, Meghin E., Mateo, Mario, Walker, Matthew G., & Olszewski, Edward W., E-mail: meghins@umich.edu. A Multi-epoch Kinematic Study of the Remote Dwarf Spheroidal Galaxy Leo II. United States. doi:10.3847/1538-4357/836/2/202.
Spencer, Meghin E., Mateo, Mario, Walker, Matthew G., and Olszewski, Edward W., E-mail: meghins@umich.edu. Mon . "A Multi-epoch Kinematic Study of the Remote Dwarf Spheroidal Galaxy Leo II". United States. doi:10.3847/1538-4357/836/2/202.
@article{osti_22663777,
title = {A Multi-epoch Kinematic Study of the Remote Dwarf Spheroidal Galaxy Leo II},
author = {Spencer, Meghin E. and Mateo, Mario and Walker, Matthew G. and Olszewski, Edward W., E-mail: meghins@umich.edu},
abstractNote = {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{sup −1} with a velocity dispersion of 7.4 ± 0.4 km s{sup −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{sup −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.},
doi = {10.3847/1538-4357/836/2/202},
journal = {Astrophysical Journal},
number = 2,
volume = 836,
place = {United States},
year = {Mon Feb 20 00:00:00 EST 2017},
month = {Mon Feb 20 00:00:00 EST 2017}
}
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