Статья

A Multimass Velocity Dispersion Model of 47 Tucanae Indicates No Evidence for an Intermediate-mass Black Hole

Christopher R. MannDepartment of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, CanadaHarvey B. RicherDepartment of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, CanadaJeremy HeylDepartment of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, CanadaJay AndersonSpace Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USAJason S. KaliraiSpace Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USAIlaria CaiazzoDepartment of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, CanadaSwantje D. MöhleDepartment of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, CanadaA. M. KneeDepartment of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, CanadaHolger BaumgardtSchool of Mathematics and Physics, University of Queensland, St. Lucia, QLD 4068, Australia

2019en

ABI

Аннотация

Abstract In this paper, we analyze stellar proper motions in the core of the globular cluster 47 Tucanae to explore the possibility of an intermediate-mass black hole (IMBH) influence on the stellar dynamics. Our use of short-wavelength photometry affords us an exceedingly clear view of stellar motions into the very center of the crowded core, yielding proper motions for >50,000 stars in the central 2′. We model the velocity dispersion profile of the cluster using an isotropic Jeans model. The density distribution is taken as a central IMBH point mass added to a combination of King templates. We individually model the general low-mass cluster objects (main sequence/giant stars), as well as the concentrated populations of heavy binary systems and dark stellar remnants. Using unbinned likelihood model fitting, we find that the inclusion of the concentrated populations in our model plays a crucial role in fitting for an IMBH mass. The concentrated binaries and stellar-mass black holes (BHs) produce a sufficient velocity dispersion signal in the core so as to make an IMBH unnecessary to fit the observations. We additionally determine that a stellar-mass BH retention fraction of ≳8.5% becomes incompatible with our observed velocities in the core.

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Идентификаторы

DOI: 10.3847/1538-4357/ab0e6d

Цитирования и источники

Цитирований: 6Использованных источников: 0

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