The Mass of the Large Magellanic Cloud from the Three-dimensional Kinematics of Its Globular Clusters
Abstract We estimate the mass of the Large Magellanic Cloud (LMC) using the kinematics of 30 LMC globular clusters (GCs). We combine proper motions measured with the Hubble Space Telescope, Gaia, or a combination of the two, from a recent study by Bennet et al. with literature line-of-sight velociti...
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Published in | The Astrophysical journal Vol. 963; no. 2; pp. 84 - 97 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Philadelphia
The American Astronomical Society
01.03.2024
IOP Publishing |
Subjects | |
Online Access | Get full text |
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Summary: | Abstract
We estimate the mass of the Large Magellanic Cloud (LMC) using the kinematics of 30 LMC globular clusters (GCs). We combine proper motions measured with the Hubble Space Telescope, Gaia, or a combination of the two, from a recent study by Bennet et al. with literature line-of-sight velocities (LOSVs) to give three components of motion. With these, we derive a 3D velocity dispersion anisotropy
β
=
−
0.72
−
1.07
+
0.62
, consistent with the GCs forming a flattened system with significant azimuthal motion. We then apply a tracer mass estimator and measure an enclosed mass
M
(
<
13.2
kpc
)
=
2.66
−
0.36
+
0.42
×
10
10
M
⊙
. This is broadly consistent with results from previous studies of the LOSVs of GCs and other luminous tracers. Assuming a cosmologically constrained Navarro–Frenk–White distribution for the dark matter, this implies a virial mass
M
virial
=
1.80
−
0.54
+
1.05
×
10
11
M
⊙
. Despite being an extrapolation by almost an order of magnitude in radius, this result is consistent with published estimates from other methods that are directly sensitive to the LMC’s total mass. Our results support the conclusion that the LMC is approximately
17
−
6
+
10
% of the Milky Way’s mass, making it a significant contributor to the Local Group potential. |
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Bibliography: | AAS50331 Interstellar Matter and the Local Universe |
ISSN: | 0004-637X 1538-4357 |
DOI: | 10.3847/1538-4357/ad1f58 |