Abstract / Description of output
We present the first kinematic analysis of the far outer halo globular
cluster (GC) population in the Local Group galaxy M31. Our sample
contains 53 objects with projected radii of ~20-130 kpc, 44 of which
have no previous spectroscopic information. GCs with projected radii
>~ 30 kpc are found to exhibit net rotation around the minor axis of
M31, in the same sense as the inner GCs, albeit with a smaller amplitude
of 79 ± 19 km s-1. The rotation-corrected
velocity dispersion of the full halo GC sample is 106 ± 12 km
s-1, which we observe to decrease with increasing
projected radius. We find compelling evidence for kinematic coherence
among GCs that project on top of halo substructure, including a clear
signature of infall for GCs lying along the northwest stream. Using the
tracer mass estimator, we estimate the dynamical mass of M31 within 200
kpc to be M M31 = (1.2-1.5) ± 0.2 ×
1012 M ⊙. This value is highly dependent on
the chosen model and assumptions within.
Original language | English |
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Article number | 33 |
Number of pages | 5 |
Journal | Astrophysical Journal Letters |
Volume | 768 |
Issue number | 2 |
DOIs | |
Publication status | Published - 10 May 2013 |
Keywords / Materials (for Non-textual outputs)
- galaxies: halos
- galaxies: individual: M31
- galaxies: kinematics and dynamics
- globular clusters: general
- Local Group