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The chemo-dynamical groups of Galactic globular clusters

Callingham, Thomas M; Cautun, Marius; Deason, Alis J; Frenk, Carlos S; Grand, Robert JJ; Marinacci, Federico

The chemo-dynamical groups of Galactic globular clusters Thumbnail


Marius Cautun

Robert JJ Grand

Federico Marinacci


We introduce a multicomponent chemo-dynamical method for splitting the Galactic population of globular clusters (GCs) into three distinct constituents: bulge, disc, and stellar halo. The latter is further decomposed into the individual large accretion events that built up the Galactic stellar halo: the Gaia–Enceladus–Sausage, Kraken and Sequoia structures, and the Sagittarius and Helmi streams. Our modelling is extensively tested using mock GC samples constructed from the AURIGA suite of hydrodynamical simulations of Milky Way (MW)-like galaxies. We find that, on average, a proportion of the accreted GCs cannot be associated with their true infall group and are left ungrouped, biasing our recovered population numbers to ∼80 per cent of their true value. Furthermore, the identified groups have a completeness and a purity of only ∼65 per cent⁠. This reflects the difficulty of the problem, a result of the large degree of overlap in energy-action space of the debris from past accretion events. We apply the method to the Galactic data to infer, in a statistically robust and easily quantifiable way, the GCs associated with each MW accretion event. The resulting groups’ population numbers of GCs, corrected for biases, are then used to infer the halo and stellar masses of the now defunct satellites that built up the halo of the MW.


Callingham, T. M., Cautun, M., Deason, A. J., Frenk, C. S., Grand, R. J., & Marinacci, F. (2022). The chemo-dynamical groups of Galactic globular clusters. Monthly Notices of the Royal Astronomical Society, 513(3), 4107-4129.

Journal Article Type Article
Acceptance Date Apr 21, 2022
Online Publication Date Apr 29, 2022
Publication Date 2022-07
Deposit Date Jun 8, 2022
Publicly Available Date Jun 8, 2022
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 513
Issue 3
Pages 4107-4129


Published Journal Article (3.4 Mb)

Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. ©: 2021 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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