Testing Fundamental Physics with Distant Star Clusters: Analysis of Observational Data on Palomar 14

Understand

We use the distant outer halo globular cluster Palomar 14 as a test case for classical vs.

• modified Newtonian dynamics (MOND).
• Previous theoretical calculations have shown that the line-of-sight velocity dispersion predicted by these theories can differ by up to a factor of three for such sparse, remote clusters like Pal 14.
• We determine the line-of-sight velocity dispersion of Palomar 14 by measuring radial velocities of 17 red giant cluster members obtained using the Very Large Telescope (VLT) and Keck telescope.