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arXiv · astro-ph/0512503

The dynamical M/L-profile and distance of the globular cluster M15

Remco van den Bosch·Tim de Zeeuw·Karl Gebhardt·Eva Noyola·Glenn van de Ven
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Abstract

We construct orbit-based axisymmetric dynamical models for the globular cluster M15 which fit groundbased line-of-sight velocities and Hubble Space Telescope line-of-sight velocities and proper motions. This allows us to constrain the variation of the mass-to-light ratio M/L as a function of radius in the cluster, and to measure the distance and inclination of the cluster. We obtain a best-fitting inclination of 60+/-15 degrees, a dynamical distance of 10.3+/-0.4 kpc and an M/L profile with a central peak. The inferred mass in the central 0.05 parsec is 3400 Msun, implying a central density of at least 7.4x10^6 Msun pc^-3. We cannot distinguish the nature of the central mass concentration. It could be an IMBH or it could be large number of compact objects, or it could be a combination. The central 4 arcsec of M15 appears to contain a rapidly spinning core, and we speculate on its origin.

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Remco van den Bosch, Tim de Zeeuw, Karl Gebhardt, Eva Noyola, Glenn van de Ven. 2005-12-21. The dynamical M/L-profile and distance of the globular cluster M15. https://doi.org/10.1086/500644

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