Probing Populations of Dark Stellar Remnants in the Globular Clusters 47 Tuc and Terzan 5 Using Pulsar Timing

Abstract

We present a new method to combine multimass equilibrium dynamical models and pulsar timing data to constrainthe mass distribution and remnant populations of Milky Way globular clusters (GCs). We first apply this method to47 Tuc, a cluster for which there exists an abundance of stellar kinematic data and which is also host to a largepopulation of millisecond pulsars. We demonstrate that the pulsar timing data allow us to place strong constraintson the overall mass distribution and remnant populations even without fitting on stellar kinematics. Our modelsfavor a small population of stellar-mass black holes (BHs) in this cluster (with a total mass of -446+ M 72 75 ), arguing against the need for a large (>2000Me) central intermediate-mass BH. We then apply the method to Terzan 5, aheavily obscured bulge cluster that hosts the largest population of millisecond pulsars of any Milky Way GC andfor which the collection of conventional stellar kinematic data is very limited. We improve existing constraints onthe mass distribution and structural parameters of this cluster and place stringent constraints on its black holecontent, finding an upper limit on the mass in BHs of ∼4000Me. This method allows us to probe the centraldynamics of GCs even in the absence of stellar kinematic data and can be easily applied to other GCs with pulsartiming data, for which data sets will continue to grow with the next generation of radio telescopes.