The structure of star clusters in the outer halo of M31

N. R. Tanvir*, A. D. Mackey, A. M. N. Ferguson, A. Huxor, J. I. Read, G. F. Lewis, M. J. Irwin, S. Chapman, R. Ibata, M. I. Wilkinson, A. W. McConnachie, N. F. Martin, M. B. Davies, T. J. Bridges

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

We present a structural analysis of halo star clusters in M31 based on deep Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) imaging. The clusters in our sample span a range in galactocentric projected distance from 13 to 100 kpc and thus reside in rather remote environments. Ten of the clusters are classical globulars, whilst four are from the Huxor et al. population of extended, old clusters. For most clusters, contamination by M31 halo stars is slight, and so the profiles can be mapped reliably to large radial distances from their centres. We find that the extended clusters are well fit by analytic King profiles with similar to 20 parsec core radii and similar to 100 parsec photometric tidal radii, or by Sersic profiles of index similar to 1 (i.e. approximately exponential). Most of the classical globulars also have large photometric tidal radii in the range 50-100 parsec; however, the King profile is a less good fit in some cases, particularly at small radii. We find 60 per cent of the classical globular clusters exhibit cuspy cores which are reasonably well described by Sersic profiles of index similar to 2-6. Our analysis also reinforces the finding that luminous classical globulars, with half-light radii

Original languageEnglish
Pages (from-to)162-184
Number of pages23
JournalMonthly Notices of the Royal Astronomical Society
Volume422
Issue number1
DOIs
Publication statusPublished - May 2012

Keywords / Materials (for Non-textual outputs)

  • galaxies: haloes
  • galaxies: star clusters: general
  • galaxies: individual: M31
  • SURFACE BRIGHTNESS PROFILES
  • DISCOVERED GLOBULAR-CLUSTERS
  • LOCAL GROUP GALAXIES
  • MILKY-WAY
  • DARK-MATTER
  • DYNAMICAL MODELS
  • ACCRETION ORIGIN
  • ANDROMEDA GALAXY
  • ACS PHOTOMETRY
  • DWARF GALAXIES

Fingerprint

Dive into the research topics of 'The structure of star clusters in the outer halo of M31'. Together they form a unique fingerprint.

Cite this