Kinematics of a globular cluster with an extended profile: NGC5694
Date Issued
2015
Author(s)
•
A. Mucciarelli
•
M. Catelan
•
M. Correnti
•
V. D'Orazi
•
C. Cortes
•
P. Amigo
•
•
Description
We are grateful to an anonymous referee for useful comments and suggestions. MB and AS acknowledges the financial support from PRIN MIUR, project: The Chemical and Dynamical Evolution of the Milky Way and Local Group Galaxies , prot. 2010LY5N2T, (PI F. Matteucci). Support for MC, PA and CC is provided by the Ministry for the Economy, Development, and Tourism's Programa Iniciativa Científica Milenio through grant IC 120009, awarded to the Millennium Institute of Astrophysics (MAS). MC also acknowledges support by Proyecto Basal PFB-06/2007 and by FONDECYT grant #1141141.
Abstract
We present a study of the kinematics of the remote globular cluster NGC5694
based on GIRAFFE@VLT medium resolution spectra. A sample of 165 individual
stars selected to lie on the Red Giant Branch in the cluster Color Magnitude
Diagram was considered. Using radial velocity and metallicity from Calcium
triplet, we were able to select 83 bona-fide cluster members. The addition of
six previously known members leads to a total sample of 89 cluster giants with
typical uncertainties <1.0 km/s in their radial velocity estimates. The sample
covers a wide range of projected distances from the cluster center, from ~0.2
arcmin to 6.5 arcmin = 23 half-light radii (r_h). We find only very weak
rotation, as typical of metal-poor globular clusters. The velocity dispersion
gently declines from a central value of sigma=6.1 km/s to sigma = 2.5 km/s at
~2 arcmin = 7.1= r_h, then it remainins flat out to the next (and last)
measured point of the dispersion profile, at ~4 arcmin = 14.0 r_h, at odds with
the predictions of isotropic King models. We show that both isotropic
single-mass non-collisional models and multi-mass anisotropic models can
reproduce the observed surface brightness and velocity dispersion profiles.
Volume
446
Issue
3
Start page
3130
Issn Identifier
0035-8711
Ads BibCode
2015MNRAS.446.3130B
Rights
open.access
File(s)![Thumbnail Image]()
Loading...
Name
stu2303.pdf
Description
PDF editoriale
Size
2.71 MB
Format
Adobe PDF
Checksum (MD5)
84f418e80a16c4e18291b27c3ae6906f