Spectroscopic signatures of extra-tidal stars around the globular clusters NGC 6656 (M22), NGC 3201 and NGC 1851 from RAVE

Kunder, A. (Andrea); Bono, Giuseppe; Piffl, Tilmann; Steinmetz, Matthias, 1966-; Grebel, Eva K.; Anguiano Jiminez, Borja; Freeman, Ken, 1940-; Kordopatis, Georges, 1985-; Zwitter, Tomaž; Scholz, Ralf-Dieter; Gibson, Brad K.; Bland-Hawthorn, J. (Joss); Seabroke, George; Boeche, Corrado; Siebert, Arnaud, 1974-; Wyse, Rosemary F. G.; Bienaymé, Olivier; Navarro, Julio F. (Julio Fernando); Siviero, Alessandro; Minchev, Ivan (Mathematics professor); Parker, Quentin A.; Reid, Warren A. (Warren Alfred); Gilmore, Gerry, 1951-; Munari, Ulisse; Helmi, A. (Amina), 1970-

Galaxy : evolution; Galaxy : formation; Galaxy : globular clusters : individual : M22; Galaxy : globular clusters : individual : NGC 1851; Galaxy : stellar content; Galaxy : structure
2014

Journal article


Rights
©2016 the Authors
Abstract

Stellar population studies of globular clusters have suggested that the brightest clusters in the Galaxy might actually be the remnant nuclei of dwarf spheroidal galaxies. If the present Galactic globular clusters formed within larger stellar systems, they are likely surrounded by extra-tidal halos and/or tails made up of stars that were tidally stripped from their parent systems. The stellar surroundings around globular clusters are therefore one of the best places to look for the remnants of an ancient dwarf galaxy. Here an attempt is made to search for tidal debris around the supernovae enriched globular clusters M22 and NGC 1851 as well as the kinematically unique cluster NGC 3201. The stellar parameters from the Radial Velocity Experiment (RAVE) are used to identify stars with RAVE metallicities, radial velocities and elemental-abundances consistent with the abundance patterns and properties of the stars in M22, NGC 1851 and NGC 3201. The discovery of RAVE stars that may be associated with M22 and NGC 1851 are reported, some of which are at projected distances of ~10 degrees away from the core of these clusters. Numerous RAVE stars associated with NGC 3201 suggest that either the tidal radius of this cluster is underestimated, or that there are some unbound stars extending a few arc minutes from the edge of the cluster's radius. No further extra-tidal stars associated with NGC 3201 could be identified. The bright magnitudes of the RAVE stars make them easy targets for high resolution follow-up observations, allowing an eventual further chemical tagging to solidify (or exclude) stars outside the tidal radius of the cluster as tidal debris. In both our radial velocity histograms of the regions surrounding NGC 1851 and NGC 3201, a peak of stars at 230 km/s is seen, consistent with extended tidal debris from omega Centauri.

Publisher
The University of Hull
Peer reviewed
Yes
Language
English
Extent
1 MB
Identifier
hull:12886

Journal

Journal title
Astronomy and astrophysics
Publication date
2014
Publisher
EDP sciences
DOI
10.1051/0004-6361/201424113
ISSN (Print)
0004-6361
ISSN (Electronic)
1432-0746
Volume
572
Start page
A30-1
End page
A30-10
Notes

This is the authors accepted manuscript of an article published in Astronomy and astrophysics, 2014, v.572.

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