EVIDENCE FOR AN ACCRETION ORIGIN FOR THE OUTER HALO GLOBULAR CLUSTER SYSTEM OF M31
- Research School of Astronomy and Astrophysics, Australian National University, Mt. Stromlo Observatory, Weston Creek, ACT 2611 (Australia)
- Department of Physics, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL (United Kingdom)
- Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom)
- Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA (United Kingdom)
- Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH (United Kingdom)
- NRC Herzberg Institute for Astrophysics, 5071 West Saanich Road, Victoria, British Columbia, V9E 2E7 (Canada)
- Observatoire de Strasbourg, 11 rue de l'Universite, F-67000, Strasbourg (France)
- School of Physics, A29, University of Sydney, NSW 2006 (Australia)
We use a sample of newly discovered globular clusters from the Pan-Andromeda Archaeological Survey (PAndAS) in combination with previously cataloged objects to map the spatial distribution of globular clusters in the M31 halo. At projected radii beyond {approx}30 kpc, where large coherent stellar streams are readily distinguished in the field, there is a striking correlation between these features and the positions of the globular clusters. Adopting a simple Monte Carlo approach, we test the significance of this association by computing the probability that it could be due to the chance alignment of globular clusters smoothly distributed in the M31 halo. We find that the likelihood of this possibility is low, below 1%, and conclude that the observed spatial coincidence between globular clusters and multiple tidal debris streams in the outer halo of M31 reflects a genuine physical association. Our results imply that the majority of the remote globular cluster system of M31 has been assembled as a consequence of the accretion of cluster-bearing satellite galaxies. This constitutes the most direct evidence to date that the outer halo globular cluster populations in some galaxies are largely accreted.
- OSTI ID:
- 21451060
- Journal Information:
- Astrophysical Journal Letters, Vol. 717, Issue 1; Other Information: DOI: 10.1088/2041-8205/717/1/L11; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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