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We use the distant outer halo globular cluster Palomar 14 as a test case forclassical vs. modified Newtonian dynamics (MOND). Previous theoreticalcalculations have shown that the line-of-sight velocity dispersion predicted bythese theories can differ by up to a factor of three for such sparse, remoteclusters like Pal 14. We determine the line-of-sight velocity dispersion ofPalomar 14 by measuring radial velocities of 17 red giant cluster membersobtained using the Very Large Telescope (VLT) and Keck telescope. The systemicvelocity of Palomar 14 is (72.28+-0.12)km/s. The derived velocity dispersion of(0.38+-0.12)km/s of the 16 definite member stars is in agreement with thetheoretical prediction for the classical Newtonian case according to Baumgardtet al. (2005). In order to exclude the possibility that a peculiar massfunction might have influenced our measurements, we derived the cluster's mainsequence mass function down to 0.53Msolar using archival images obtained withthe Hubble Space Telescope. We found a mass function slope of 1.27+-0.44, whichis, compared to the canonical mass function, a significantly shallower slope.The derived lower limit on the cluster's mass is higher than the theoreticallypredicted mass in case of MOND. Our data are consistent with a central densityof 0.1 Msolar pc^-3. We need no dark matter in Palomar 14. If the cluster is ona circular orbit, our spectroscopic and photometric results argue against MOND,unless this cluster experienced significant mass loss.

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