dc.contributor.author | Mackey, A. D. | en_US |
dc.contributor.author | Ferguson, A. M. N. | en_US |
dc.contributor.author | Irwin, M. J. | en_US |
dc.contributor.author | Martin, N. F. | en_US |
dc.contributor.author | Huxor, A. P. | en_US |
dc.contributor.author | Tanvir, N. R. | en_US |
dc.contributor.author | Chapman, S. C. | en_US |
dc.contributor.author | Ibata, R. A. | en_US |
dc.contributor.author | Lewis, G. F. | en_US |
dc.contributor.author | McConnachie, A. W. | en_US |
dc.date.accessioned | 2014-03-12T19:20:55Z | |
dc.date.available | 2014-03-12T19:20:55Z | |
dc.date.issued | 2009-09-08 | en_US |
dc.identifier.citation | Mackey, A. D., A. M. N. Ferguson, M. J. Irwin, N. F. Martin, et al. 2009. "Deep Gemini/GMOS imaging of an extremely isolated globular cluster in the Local Group." Monthly Notices of the Royal Astronomical Society 401:533. | en_US |
dc.identifier.issn | 0035-8711 | |
dc.identifier.uri | http://hdl.handle.net/10222/45378 | |
dc.identifier.uri | http://dx.doi.org/10.1111/j.1365-2966.2009.15678.x | |
dc.description.abstract | We report on deep imaging of a remote M31 globular cluster, MGC1, obtained with Gemini/GMOS. Our colour-magnitude diagram for this object extends ~5 magnitudes below the tip of the red giant branch and exhibits features consistent with an ancient metal-poor stellar population, including a long, well-populated horizontal branch. The red giant branch locus suggests MGC1 has a metal abundance [M/H] ~ -2.3. We measure the distance to MGC1 and find that it lies ~160 kpc in front of M31 with a distance modulus of 23.95 +/- 0.06. Combined with its large projected separation of 117 kpc from M31 this implies a deprojected radius of Rgc = 200 +/- 20 kpc, rendering it the most isolated known globular cluster in the Local Group by some considerable margin. We construct a radial brightness profile for MGC1 and show that it is both centrally compact and rather luminous, with Mv = -9.2. Remarkably, the cluster profile shows no evidence for a tidal limit and we are able to trace it to a radius of at least 450 pc, and possibly as far as ~900 pc. The profile exhibits a power-law fall-off with exponent -2.5, breaking to -3.5 in its outermost parts. This core-halo structure is broadly consistent with expectations derived from numerical models, and suggests that MGC1 has spent many gigayears in isolation. | en_US |
dc.relation.ispartof | Monthly Notices of the Royal Astronomical Society | |
dc.title | Deep Gemini/GMOS imaging of an extremely isolated globular cluster in the Local Group | en_US |
dc.title.alternative | arXiv:0909.1456 [astro-ph] | en_US |
dc.type | article | en_US |
dc.identifier.volume | 401 | |
dc.identifier.startpage | 533 | en_US |