Open AccessThe Dynamical Mass‐to‐Light Ratio Profile and Distance of the Globular Cluster M15
Author(s) -
Remco C. E. van den Bosch,
P. T. de Zeeuw,
Karl Gebhardt,
Eva Noyola,
Glenn van de Ven
Publication year - 2006
Publication title -
the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.1086/500644
Subject(s) - globular cluster , physics , astrophysics , mass ratio , mass to light ratio , radius , cluster (spacecraft) , line of sight , mass segregation , orbit (dynamics) , astronomy , galaxy , luminosity function , luminosity , computer security , computer science , programming language , aerospace engineering , engineering
We construct orbit-based axisymmetric dynamical models for the globularcluster M15 which fit groundbased line-of-sight velocities and Hubble SpaceTelescope line-of-sight velocities and proper motions. This allows us toconstrain the variation of the mass-to-light ratio M/L as a function of radiusin the cluster, and to measure the distance and inclination of the cluster. Weobtain a best-fitting inclination of 60+/-15 degrees, a dynamical distance of10.3+/-0.4 kpc and an M/L profile with a central peak. The inferred mass in thecentral 0.05 parsec is 3400 Msun, implying a central density of at least7.4x10^6 Msun pc^-3. We cannot distinguish the nature of the central massconcentration. It could be an IMBH or it could be large number of compactobjects, or it could be a combination. The central 4 arcsec of M15 appears tocontain a rapidly spinning core, and we speculate on its origin.Comment: 10 pages, 10 figures, 4 tables, emulateapj, Accepted for publication in ApJ, v2: fixed layou
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