MONDian dynamical modeling of NGC 288 with $\beta \ne 0$

Abstract

NGC 288 is a diffuse Galactic globular cluster, it is remarkable in that its low density results in internal accelerations being below the critical MOND $a_0$ acceleration throughout. This makes it an ideal testing ground for MONDian gravity, as the details of the largely unknown transition function between the Newtonian and modified regimes become unimportant. Further, exact analytical solutions exist for isothermal spherical equilibrium structures in MOND, allowing for arbitrary values of the anisotropy parameter, $\beta$. In this paper we use observations of the velocity dispersion profile of NGC 288, which is in fact isothermal, as dynamical constraints on MONDian models for this cluster, where the remaining free parameters are adjusted to fit the observed surface brightness profile. We find the optimal fit requires $\beta =0$, an isotropic solution with a total mass of $3.5\pm 1.1\times 10^4{M}_{\odot }$.

7 Pages, 7 Figures, Accepted for Publication in MNRAS

References in corpus (6)

• Halo globular clusters observed with AAOmega: dark matter content, metallicity and tidal heating
• Measuring Consistent Masses for 25 Milky Way Globular Clusters
• The Gaia-ESO Survey: Kinematics of seven Galactic globular clusters
• The photometric evolution of star clusters and the preferential loss of low-mass bodies - with an application to globular clusters
• Using globular clusters to test gravity in the weak acceleration regime: NGC 7099
• Searching in the dark: the dark mass content of the Milky Way globular clusters NGC288 and NGC6218

Cited by in corpus (2)

• Asymptotic kinematics of Globular Clusters: the emergence of a Tully-Fisher relation
• MONDian predictions for Newtonian M/L ratios for ultrafaint dSphs