Jennifer A. Johnson et al. 1999 ApJ 527 199 doi:10.1086/308066
Jennifer A. Johnson1,4, Michael Bolte1, Peter B. Stetson2, James E. Hesser2 and Rachel S. Somerville3
Show affiliationsWe present V, V-I color-magnitude diagrams (CMDs) for three old star clusters in the Large Magellanic Cloud (LMC): NGC 1466, NGC 2257, and Hodge 11. Our data extend ~3 mag below the main-sequence turnoff, allowing us to determine accurate relative ages and the blue straggler frequencies. Based on a differential comparison of the CMDs, any age difference between the three LMC clusters is less than 1.5 Gyr. Comparing their CMDs to those of M92 and M3, the LMC clusters, unless their published metallicities are significantly in error, are the same age as the old Galactic globulars. The similar ages to Galactic globulars are shown to be consistent with hierarchial clustering models of galaxy formation. The blue straggler frequencies are also similar to those of Galactic globular clusters. We derive a true distance modulus to the LMC of (m - M)0 = 18.46 ± 0.09 [assuming (m - M)0 = 14.61 for M92] using these three LMC clusters.
blue stragglers; globular clusters: individual (NGC 1466, NGC 2257, Hodge 11); Magellanic Clouds
Issue 1 (1999 December 10)
Received 1999 February 16, accepted for publication 1999 June 30
Jennifer A. Johnson et al. 1999 ApJ 527 199
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