Two kinematically distinct old globular cluster populations in the Large Magellanic Cloud

DOI: 
10.1093/mnrasl/sly240
Publication date: 
01/03/2019
Main author: 
Piatti, Andrés E.
IAA authors: 
Alfaro, Emilio J.
Authors: 
Piatti, Andrés E.;Alfaro, Emilio J.;Cantat-Gaudin, Tristan
Journal: 
Monthly Notices of the Royal Astronomical Society
Refereed: 
Yes
Publication type: 
Article
Volume: 
484
Pages: 
L19-L23
Abstract: 
We report results of proper motions of 15 known Large Magellanic Cloud (LMC) old globular clusters (GCs) derived from the Gaia DR2 data sets. When these mean proper motions are gathered with existent radial velocity measurements to compose the GCs' velocity vectors, we found that the projection of the velocity vectors on to the LMC plane and those perpendicular to it tells us about two distinct kinematic GC populations. Such a distinction becomes clear if the GCs are split at a perpendicular velocity of 10 km s<SUP>-1</SUP> (absolute value). The two different kinematic groups also exhibit different spatial distributions. Those with smaller vertical velocities are a part of the LMC disc, while those with larger values are closely distributed like a spherical component. Since GCs in both kinematic-structural components share similar ages and metallicities, we speculate with the possibility that their origins could have occurred through a fast collapse that formed halo and disc concurrently.
Database: 
ADS
SCOPUS
URL: 
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85079662283&doi=10.1093%2fmnrasl%2fsly240&partnerID=40&md5=54d94a060c150aacab67d498205a9ed3
ADS Bibcode: 
2019MNRAS.484L..19P
Keywords: 
galaxies: individual: LMC;galaxies: star clusters: general;Astrophysics - Astrophysics of Galaxies