Based on observations made with European Southern Observatory telescopes at the Paranal Observatory under programme ID 081.B-0428(A).
A low surface brightness halo surrounding the globular cluster NGC 5694★
Article first published online: 7 OCT 2011
© 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS
Monthly Notices of the Royal Astronomical Society
Volume 417, Issue 4, pages 2411–2416, November 2011
How to Cite
Correnti, M., Bellazzini, M., Dalessandro, E., Mucciarelli, A., Monaco, L. and Catelan, M. (2011), A low surface brightness halo surrounding the globular cluster NGC 5694. Monthly Notices of the Royal Astronomical Society, 417: 2411–2416. doi: 10.1111/j.1365-2966.2011.19058.x
- Issue published online: 2 NOV 2011
- Article first published online: 7 OCT 2011
- Accepted 2011 May 11. Received 2011 April 29; in original form 2011 February 22
- Galaxy: formation;
- globular clusters: individual: NGC 5694
We report on the discovery of an extended stellar halo surrounding the distant Galactic globular cluster NGC 5694, based on new deep (V≃ 24.5) wide-field (24 × 20 arcmin2) photometry acquired with the VIMOS at the VLT. Stars with colour and magnitude consistent with the main sequence of the cluster are clearly identified out to r≃ 9 arcmin (≃93 pc) from the cluster centre, much beyond the tidal radius of the King model that best fits the inner profile (rt= 3.15 arcmin). We do not find a clear end of the structure within our field. The overall observed profile cannot be properly fitted with either a King model, an Elson et al. model or a Wilson model; however, it is very smooth and does not show any sign of the break near the tidal radius that is typically observed in stellar systems with tidal tails. The density map we derived does not show evidence of tidal tails, within the considered field. The extra-tidal component contains ≃ 3.5 per cent of the cluster light (mass) and has a surface density profile falling as ∼r−3.2. The possible origin of the detected structure is discussed, as a clear-cut conclusion cannot be reached with the available data.