University of Surrey

Test tubes in the lab Research in the ATI Dance Research

Biases in the determination of dynamical parameters of star clusters: today and in the Gaia era

Sollima, A, Baumgardt, H, Zocchi, A, Balbinot, E, Gieles, M, Henault-Brunet, V and Varri, AL (2015) Biases in the determination of dynamical parameters of star clusters: today and in the Gaia era Monthly Notices of the Royal Astronomical Society.

Full text not available from this repository.

Abstract

The structural and dynamical properties of star clusters are generally derived by means of the comparison between steady-state analytic models and the available observables. With the aim of studying the biases of this approach, we fitted different analytic models to simulated observations obtained from a suite of direct N-body simulations of star clusters in different stages of their evolution and under different levels of tidal stress to derive mass, mass function and degree of anisotropy. We find that masses can be under/over-estimated up to 50% depending on the degree of relaxation reached by the cluster, the available range of observed masses and distances of radial velocity measures from the cluster center and the strength of the tidal field. The mass function slope appears to be better constrainable and less sensitive to model inadequacies unless strongly dynamically evolved clusters and a non-optimal location of the measured luminosity function are considered. The degree and the characteristics of the anisotropy developed in the N-body simulations are not adequately reproduced by popular analytic models and can be detected only if accurate proper motions are available. We show how to reduce the uncertainties in the mass, mass-function and anisotropy estimation and provide predictions for the improvements expected when Gaia proper motions will be available in the near future.

Item Type: Article
Authors :
NameEmailORCID
Sollima, AUNSPECIFIEDUNSPECIFIED
Baumgardt, HUNSPECIFIEDUNSPECIFIED
Zocchi, AUNSPECIFIEDUNSPECIFIED
Balbinot, Ee.balbinot@surrey.ac.ukUNSPECIFIED
Gieles, Mm.gieles@surrey.ac.ukUNSPECIFIED
Henault-Brunet, Vv.henault-brunet@surrey.ac.ukUNSPECIFIED
Varri, ALUNSPECIFIEDUNSPECIFIED
Date : 11 May 2015
Uncontrolled Keywords : astro-ph.SR, astro-ph.SR, astro-ph.GA
Related URLs :
Depositing User : Symplectic Elements
Date Deposited : 17 May 2017 13:38
Last Modified : 17 May 2017 15:12
URI: http://epubs.surrey.ac.uk/id/eprint/839902

Actions (login required)

View Item View Item

Downloads

Downloads per month over past year


Information about this web site

© The University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom.
+44 (0)1483 300800