The structure of star clusters in the outer halo of M31
(2012) In Monthly Notices of the Royal Astronomical Society 422(1). p.162-184- Abstract
- 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... (More)
- 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 <10 parsec, are present out to radii of at least 100 kpc in M31, which is in contrast to the situation in the Milky Way where such clusters (other than the unusual object NGC 2419) are absent beyond 40 kpc. (Less)
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https://lup.lub.lu.se/record/2813030
- author
- organization
- publishing date
- 2012
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- galaxies: haloes, galaxies: star clusters: general, galaxies:, individual: M31
- in
- Monthly Notices of the Royal Astronomical Society
- volume
- 422
- issue
- 1
- pages
- 162 - 184
- publisher
- Oxford University Press
- external identifiers
-
- wos:000303912600032
- scopus:84859881278
- ISSN
- 1365-2966
- DOI
- 10.1111/j.1365-2966.2012.20590.x
- language
- English
- LU publication?
- yes
- id
- ece9eb7c-6f19-4c9b-8b59-b587ab0d6454 (old id 2813030)
- date added to LUP
- 2016-04-01 09:52:36
- date last changed
- 2024-01-06 02:05:17
@article{ece9eb7c-6f19-4c9b-8b59-b587ab0d6454, abstract = {{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 <10 parsec, are present out to radii of at least 100 kpc in M31, which is in contrast to the situation in the Milky Way where such clusters (other than the unusual object NGC 2419) are absent beyond 40 kpc.}}, author = {{Tanvir, N. R. and Mackey, A. D. and Ferguson, A. M. N. and Huxor, A. and Read, J. I. and Lewis, G. F. and Irwin, M. J. and Chapman, S. and Ibata, R. and Wilkinson, M. I. and McConnachie, A. W. and Martin, N. F. and Davies, Melvyn B and Bridges, T. J.}}, issn = {{1365-2966}}, keywords = {{galaxies: haloes; galaxies: star clusters: general; galaxies:; individual: M31}}, language = {{eng}}, number = {{1}}, pages = {{162--184}}, publisher = {{Oxford University Press}}, series = {{Monthly Notices of the Royal Astronomical Society}}, title = {{The structure of star clusters in the outer halo of M31}}, url = {{https://lup.lub.lu.se/search/files/1346532/2970512.pdf}}, doi = {{10.1111/j.1365-2966.2012.20590.x}}, volume = {{422}}, year = {{2012}}, }