Image Details
Caption: Figure 1.
Predicted and observed velocity dispersions of recently measured dSph satellites of M31. Each bin along the
x-axis corresponds to the number of each dwarf for And XVII through And XXIX. The predictions from Paper I are shown without
adjustment as circles for
* = 1 (lower points), 2 (middle points), and 4
M
☉/
L
☉ (upper points). Circles are filled if the dwarf is in the isolated regime for the assumed
* and open if it is dominated by the external field of M31. The error bars on the predictions include both observational uncertainties
in the photometry and a factor of two uncertainty in
* around
* = 2
M
☉/
L
☉. Observed velocity dispersions are taken from Tollerud et al. (2012, small squares), Tollerud et al. (2013, large squares),
and Collins et al. (2013, triangles or, in the case of upper limits, horizontal bars). The number of stars used to determine
each velocity dispersion is shown next to the corresponding datum. Points appear in the chronological order of their appearance
in the literature from left to right within each bin. Collins et al. (2013) find that And XXVII is not in equilibrium, in
contradiction to a necessary assumption of the analysis.
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