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Stellar kinematics and metallicities in the Leo I dwarf spheroidal galaxy: wide-field implications for galactic evolution

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Stellar kinematics and metallicities in the Leo I dwarf spheroidal galaxy: wide-field implications for galactic evolution. / Koch, Andreas; Wilkinson, Mark I.; Kleyna, Jan et al.
In: The Astrophysical Journal, Vol. 657, No. 1, 01.03.2007, p. 241-261.

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Harvard

Koch, A, Wilkinson, MI, Kleyna, J, Gilmore, G, Grebel, EK, Mackey, AD, Wyn Evans, N & Wyse, RFG 2007, 'Stellar kinematics and metallicities in the Leo I dwarf spheroidal galaxy: wide-field implications for galactic evolution', The Astrophysical Journal, vol. 657, no. 1, pp. 241-261. https://doi.org/10.1086/510879

APA

Koch, A., Wilkinson, M. I., Kleyna, J., Gilmore, G., Grebel, E. K., Mackey, A. D., Wyn Evans, N., & Wyse, R. F. G. (2007). Stellar kinematics and metallicities in the Leo I dwarf spheroidal galaxy: wide-field implications for galactic evolution. The Astrophysical Journal, 657(1), 241-261. https://doi.org/10.1086/510879

Vancouver

Koch A, Wilkinson MI, Kleyna J, Gilmore G, Grebel EK, Mackey AD et al. Stellar kinematics and metallicities in the Leo I dwarf spheroidal galaxy: wide-field implications for galactic evolution. The Astrophysical Journal. 2007 Mar 1;657(1):241-261. doi: 10.1086/510879

Author

Koch, Andreas ; Wilkinson, Mark I. ; Kleyna, Jan et al. / Stellar kinematics and metallicities in the Leo I dwarf spheroidal galaxy : wide-field implications for galactic evolution. In: The Astrophysical Journal. 2007 ; Vol. 657, No. 1. pp. 241-261.

Bibtex

@article{7bce3bf71da9432f9d7084a29d0e186c,
title = "Stellar kinematics and metallicities in the Leo I dwarf spheroidal galaxy: wide-field implications for galactic evolution",
abstract = "We present low-resolution spectroscopy of 120 red giants in the Galactic satellite dwarf spheroidal (dSph) Leo I, obtained with GeminiN GMOS and Keck DEIMOS. We find stars with velocities consistent with membership of Leo I out to 1.3 King tidal radii. By measuring accurate radial velocities with a median measurement error of 4.6 km s-1, we find a mean systemic velocity of 284.2 km s-1 with a global velocity dispersion of 9.9 km s-1. The dispersion profile is consistent with being flat out to the last data point. We show that a marginally significant rise in the radial dispersion profile at a radius of 3' is not associated with any real localized kinematical substructure. Given its large distance from the Galaxy, tides are not likely to have affected the velocity dispersion, a statement we support from a quantitative kinematical analysis, as we observationally reject the occurrence of a significant apparent rotational signal or an asymmetric velocity distribution. Mass determinations adopting both isotropic stellar velocity dispersions and more general models yield an M/L of 24, which is consistent with the presence of a significant dark halo with a mass of about 3 × 107 M☉, in which the luminous component is embedded. This suggests that Leo I exhibits dark matter properties similar to those of other dSphs in the Local Group. Our data allowed us also to determine metallicities for 58 of the targets. We find a mildly metal-poor mean of -1.31 dex and a full spread covering 1 dex. In contrast to the majority of dSphs, Leo I appears to show no radial gradient in its metallicities, which points to a negligible role of external influences in this galaxy's evolution.",
author = "Andreas Koch and Wilkinson, {Mark I.} and Jan Kleyna and Gerard Gilmore and Grebel, {Eva K.} and Mackey, {A. Dougal} and {Wyn Evans}, N. and Wyse, {Rosemary F. G.}",
year = "2007",
month = mar,
day = "1",
doi = "10.1086/510879",
language = "English",
volume = "657",
pages = "241--261",
journal = "The Astrophysical Journal",
issn = "0004-637X",
publisher = "Institute of Physics Publishing",
number = "1",

}

RIS

TY - JOUR

T1 - Stellar kinematics and metallicities in the Leo I dwarf spheroidal galaxy

T2 - wide-field implications for galactic evolution

AU - Koch, Andreas

AU - Wilkinson, Mark I.

AU - Kleyna, Jan

AU - Gilmore, Gerard

AU - Grebel, Eva K.

AU - Mackey, A. Dougal

AU - Wyn Evans, N.

AU - Wyse, Rosemary F. G.

PY - 2007/3/1

Y1 - 2007/3/1

N2 - We present low-resolution spectroscopy of 120 red giants in the Galactic satellite dwarf spheroidal (dSph) Leo I, obtained with GeminiN GMOS and Keck DEIMOS. We find stars with velocities consistent with membership of Leo I out to 1.3 King tidal radii. By measuring accurate radial velocities with a median measurement error of 4.6 km s-1, we find a mean systemic velocity of 284.2 km s-1 with a global velocity dispersion of 9.9 km s-1. The dispersion profile is consistent with being flat out to the last data point. We show that a marginally significant rise in the radial dispersion profile at a radius of 3' is not associated with any real localized kinematical substructure. Given its large distance from the Galaxy, tides are not likely to have affected the velocity dispersion, a statement we support from a quantitative kinematical analysis, as we observationally reject the occurrence of a significant apparent rotational signal or an asymmetric velocity distribution. Mass determinations adopting both isotropic stellar velocity dispersions and more general models yield an M/L of 24, which is consistent with the presence of a significant dark halo with a mass of about 3 × 107 M☉, in which the luminous component is embedded. This suggests that Leo I exhibits dark matter properties similar to those of other dSphs in the Local Group. Our data allowed us also to determine metallicities for 58 of the targets. We find a mildly metal-poor mean of -1.31 dex and a full spread covering 1 dex. In contrast to the majority of dSphs, Leo I appears to show no radial gradient in its metallicities, which points to a negligible role of external influences in this galaxy's evolution.

AB - We present low-resolution spectroscopy of 120 red giants in the Galactic satellite dwarf spheroidal (dSph) Leo I, obtained with GeminiN GMOS and Keck DEIMOS. We find stars with velocities consistent with membership of Leo I out to 1.3 King tidal radii. By measuring accurate radial velocities with a median measurement error of 4.6 km s-1, we find a mean systemic velocity of 284.2 km s-1 with a global velocity dispersion of 9.9 km s-1. The dispersion profile is consistent with being flat out to the last data point. We show that a marginally significant rise in the radial dispersion profile at a radius of 3' is not associated with any real localized kinematical substructure. Given its large distance from the Galaxy, tides are not likely to have affected the velocity dispersion, a statement we support from a quantitative kinematical analysis, as we observationally reject the occurrence of a significant apparent rotational signal or an asymmetric velocity distribution. Mass determinations adopting both isotropic stellar velocity dispersions and more general models yield an M/L of 24, which is consistent with the presence of a significant dark halo with a mass of about 3 × 107 M☉, in which the luminous component is embedded. This suggests that Leo I exhibits dark matter properties similar to those of other dSphs in the Local Group. Our data allowed us also to determine metallicities for 58 of the targets. We find a mildly metal-poor mean of -1.31 dex and a full spread covering 1 dex. In contrast to the majority of dSphs, Leo I appears to show no radial gradient in its metallicities, which points to a negligible role of external influences in this galaxy's evolution.

U2 - 10.1086/510879

DO - 10.1086/510879

M3 - Journal article

VL - 657

SP - 241

EP - 261

JO - The Astrophysical Journal

JF - The Astrophysical Journal

SN - 0004-637X

IS - 1

ER -