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

Understand

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/L_V<6.7 at the 90% confidence level) or within the radius of the furthest tracer (M/L_V<8.1 at the 90% confidence level).