Discrete dynamical modelling of omega Centauri

Дата и время публикации : 2013-08-22T08:37:46Z

Авторы публикации и институты :
Laura L. Watkins (MPIA)
Glenn van de Ven (MPIA)
Mark den Brok (Utah)
Remco C. E. van den Bosch (MPIA)

Ссылка на журнал-издание: Ссылка на журнал-издание не найдена
Коментарии к cтатье: 14 pages + 4 page appendix, 7 figures, 3 tables; accepted by MNRAS
Первичная категория: astro-ph.GA

Все категории : astro-ph.GA

Краткий обзор статьи: We present a new framework for modelling discrete kinematic data. Current techniques typically involve binning. Our approach works directly with the discrete data and uses maximum-likelihood methods to assess the probability of the dataset given model predictions. We avoid making hard cuts on the datasets by allowing for a contaminating population in our models. We apply our models to discrete proper-motion and line-of-sight-velocity data of Galactic globular cluster omega Centauri and find a mildly radial velocity anisotropy beta = 0.10 +/- 0.02, an inclination angle i = 50 +/- 1 deg, a V-band mass-to-light ratio Upsilon = 2.71 +/- 0.05 Msun/Lsun and a distance d = 4.59 +/- 0.08 kpc. All parameters are in agreement with previous studies, demonstrating the feasibility of our methods. We find that the models return lower distances and higher mass-to-light ratios than expected when we include proper motion stars with high errors or for which there is some blending. We believe this not a fault of our models but is instead due to underestimates or missing systematic uncertainties in the provided errors.

Category: Physics