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Current velocity data on dwarf galaxy NGC1052-DF2 do not constrain it to lack dark matter

Martin, Nicolas F., Collins, Michelle L. M., Longeard, Nicolas and Tollerud, Erik (2018) Current velocity data on dwarf galaxy NGC1052-DF2 do not constrain it to lack dark matter Astrophysical Journal Letters, 859 (L5). pp. 1-5.

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Abstract

It was recently proposed that the globular cluster system of the very low surface-brightness galaxy NGC1052-DF2 is dynamically very cold, leading to the conclusion that this dwarf galaxy has little or no dark matter. Here, we show that a robust statistical measure of the velocity dispersion of the tracer globular clusters implies a mundane velocity dispersion and a poorly constrained mass-to-light ratio. Models that include the possibility that some of the tracers are field contaminants do not yield a more constraining inference. We derive only a weak constraint on the mass-to-light ratio of the system within the half-light radius (M/LV < 6.7 at the 90-percent confidence level) or within the radius of the furthest tracer (M/LV < 8.1 at the 90-percent confidence level). This limit may imply a mass-to-light ratio on the low end for a dwarf galaxy but many Local Group dwarf galaxies fall well within this contraint. With this study, we emphasize the need to reliably account for measurement uncertainties and to stay as close as possible to the data when determining dynamical masses from very small data sets of tracers.

Item Type: Article
Divisions : Faculty of Engineering and Physical Sciences > Physics
Authors :
NameEmailORCID
Martin, Nicolas F.
Collins, Michelle L. M.m.collins@surrey.ac.uk
Longeard, Nicolas
Tollerud, Erik
Date : 17 May 2018
DOI : 10.3847/2041-8213/aac216
Copyright Disclaimer : Copyright 2018. The American Astronomical Society. All rights reserved.
Uncontrolled Keywords : Galaxies: kinematics and dynamics. Methods: statistical.
Depositing User : Clive Harris
Date Deposited : 10 May 2018 10:41
Last Modified : 16 Jan 2019 19:09
URI: http://epubs.surrey.ac.uk/id/eprint/846394

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