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Tidal stripping as a mechanism for placing globular clusters on wide orbits : The case of MGC1 in M31

Andersson, Eric P. LU and Davies, Melvyn B. LU (2019) In Monthly Notices of the Royal Astronomical Society 485(3). p.4134-4149
Abstract

The globular clusters of large spiral galaxies can be divided into two populations: one that formed in situ and one that comprises clusters tidally stripped away from other galaxies. In this paper, we investigate the contribution to the outer globular cluster population in the M31 galaxy through donation of clusters from dwarf galaxies. We test this numerically by comparing the contribution of globular clusters from simulated encounters to the observed M31 globular cluster population. To constrain our simulations, we specifically investigate the outermost globular cluster in the M31 system, MGC1. The remote location of MGC1 favours the idea of it being captured; however, the cluster is devoid of features associated with tidal... (More)

The globular clusters of large spiral galaxies can be divided into two populations: one that formed in situ and one that comprises clusters tidally stripped away from other galaxies. In this paper, we investigate the contribution to the outer globular cluster population in the M31 galaxy through donation of clusters from dwarf galaxies. We test this numerically by comparing the contribution of globular clusters from simulated encounters to the observed M31 globular cluster population. To constrain our simulations, we specifically investigate the outermost globular cluster in the M31 system, MGC1. The remote location of MGC1 favours the idea of it being captured; however, the cluster is devoid of features associated with tidal interactions. Hence, we separate simulations where tidal features are present and where they are hidden. We find that our simulated encounters can place clusters on MGC1-like orbits. In addition, we find that tidal stripping of clusters from dwarf galaxies leaves them on orbits having a range of separations, broadly matching those observed in M31. We find that the specific energies of globular clusters captured by M31 closely match those of the incoming host dwarf galaxies. Furthermore, in our simulations we find an equal number of accreted clusters on co-rotating and counter-rotating orbits within M31 and use this to infer the fraction of clusters that has been accreted. We find that even close in roughly 50 per cent of the clusters are accreted, while this figure increases to over 80 per cent further out.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Galaxies: individual: M31, Galaxies: star clusters: general
in
Monthly Notices of the Royal Astronomical Society
volume
485
issue
3
pages
16 pages
publisher
Oxford University Press (OUP)
external identifiers
  • scopus:85067039983
ISSN
0035-8711
DOI
10.1093/mnras/stz709
language
English
LU publication?
yes
id
6d7077c2-8390-4087-b119-607054d5acb5
date added to LUP
2019-07-01 12:25:16
date last changed
2019-07-16 04:13:46
@article{6d7077c2-8390-4087-b119-607054d5acb5,
  abstract     = {<p>The globular clusters of large spiral galaxies can be divided into two populations: one that formed in situ and one that comprises clusters tidally stripped away from other galaxies. In this paper, we investigate the contribution to the outer globular cluster population in the M31 galaxy through donation of clusters from dwarf galaxies. We test this numerically by comparing the contribution of globular clusters from simulated encounters to the observed M31 globular cluster population. To constrain our simulations, we specifically investigate the outermost globular cluster in the M31 system, MGC1. The remote location of MGC1 favours the idea of it being captured; however, the cluster is devoid of features associated with tidal interactions. Hence, we separate simulations where tidal features are present and where they are hidden. We find that our simulated encounters can place clusters on MGC1-like orbits. In addition, we find that tidal stripping of clusters from dwarf galaxies leaves them on orbits having a range of separations, broadly matching those observed in M31. We find that the specific energies of globular clusters captured by M31 closely match those of the incoming host dwarf galaxies. Furthermore, in our simulations we find an equal number of accreted clusters on co-rotating and counter-rotating orbits within M31 and use this to infer the fraction of clusters that has been accreted. We find that even close in roughly 50 per cent of the clusters are accreted, while this figure increases to over 80 per cent further out.</p>},
  author       = {Andersson, Eric P. and Davies, Melvyn B.},
  issn         = {0035-8711},
  language     = {eng},
  month        = {02},
  number       = {3},
  pages        = {4134--4149},
  publisher    = {Oxford University Press (OUP)},
  series       = {Monthly Notices of the Royal Astronomical Society},
  title        = {Tidal stripping as a mechanism for placing globular clusters on wide orbits : The case of MGC1 in M31},
  url          = {http://dx.doi.org/10.1093/mnras/stz709},
  doi          = {10.1093/mnras/stz709},
  volume       = {485},
  year         = {2019},
}