Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/230871

Title

The SLUGGS Survey: globular cluster system kinematics and substructure in NGC 4365

Author(s)

Blom, Christina;  Forbes, Duncan A.;  Brodie, Jean P.;  Foster, Caroline;  Romanowsky, Aaron J.;  Spitler, Lee R.;  Strader, Jay

Abstract

We present a kinematic analysis of the globular cluster (GC) system of the giant elliptical galaxy NGC 4365 and find several distinct kinematic substructures. This analysis is carried out using radial velocities for 269 GCs, obtained with the DEIMOS instrument on the Keck II telescope as part of the SAGES Legacy Unifying Globulars and Galaxies Survey (SLUGGS). We find that each of the three (formerly identified) GC colour subpopulations reveal distinct rotation properties. The rotation of the green GC subpopulation is consistent with the bulk of NGC 4365's stellar light, which 'rolls' about the photometric major axis. The blue and red GC subpopulations show 'normal' rotation about the minor axis. We also find that the red GC subpopulation is rotationally dominated beyond 2.5 arcmin (~17 kpc) and that the root mean squared velocity of the green subpopulation declines sharply with radius suggesting a possible bias towards radial orbits relative to the other GC subpopulations. Additionally, we find a population of low velocity GCs that form a linear structure running from the SW to the NE across NGC 4365 which aligns with the recently reported stellar stream towards NGC 4342. These low velocity GCs have g'-i' colours consistent with the overall NGC 4365 GC system but have velocities consistent with the systemic velocity of NGC 4342. We discuss the possible formation scenarios for the three GC subpopulations as well as the possible origin of the low velocity GC population.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Astrophysics and Supercomputing

Source

Monthly Notices of the Royal Astronomical Society, Vol. 426, no. 3 (Nov 2012), pp. 1959-1971

Publication year

2012

FOR Code(s)

0201 Astronomical and Space Sciences

Keyword(s)

Elliptical and lenticular galaxies;  Globular clusters;  NGC 4365

Publisher

Wiley-Blackwell

ISSN

0035-8711

Publisher URL

http://dx.doi.org/10.1111/j.1365-2966.2012.21795.x

Copyright

Copyright © 2012 The Authors. Journal compilation copyright © 2012 Royal Astronomical Society.

Peer reviewed