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On the globular cluster NGC 5694

University of British Columbia

We present CCD photometry of the distant globular cluster NGC 5694. Colour-magnitude diagrams and a colour-colour diagram using U, B & V data are shown. We find the reddening in the direction of NGC 5694 to be E(B -V) = 0.10 ± 0.02. The metallicity is determined from (U — B)₁ ₀ as [Fe/H]= —2.05 ± 0.20. We place an upper limit on the distance of NGC 5694 from the sun of R < 33.4 Kpc. We do not detect conventional Blue Straggler stars in NGC 5694. If these stars are present, they are in a magnitude range which is at the limit of our photometry. In addition to the known blue horizontal branch, we detect a sparsely populated red horizontal branch, which could be identified as an evolved population of Blue Straggler Stars. We also detect a very bright and blue population of stars in the core region of the cluster. The latter two populations can not be positively confirmed due to large photometric errors resulting from crowding in the cluster centre. A Michie-King model fit to the surface brightness profile yields a core radius of r[sub c] = 3”/51 and a concentration parameter c = 1.85. We do not detect indications of a collapsed core in NGC 5694. We outline an improved method for finding the centres of globular clusters, which is used to determine the centre of the cluster to a high degree of accuracy.

Thesis/Dissertation

application/pdf

2009-01-09

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http://hdl.handle.net/2429/3491

Geophysics

University of British Columbia

UBCV

DSpace