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Three Populous Clusters Discovered to be in the LMC Age Gap

Ata Sarajedini
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Abstract

In the process of searching the Hubble Space Telescope archive, we have serendipitously discovered three populous Large Magellanic Cloud (LMC) clusters with ages that place them in the LMC `age gap.'. These clusters - NGC 2155, SL663, and NGC 2121 - turn out to have [Fe/H] ~ -1.0 and ages of ~4 Gyr. This puts them in the age gap between the intermediate-age LMC clusters, the oldest of which are ~2.5 Gyr old, and ESO121-SC03, which has an age of ~9 Gyr. The addition of these three clusters to the LMC age - metallicity relation has reduced the discrepancy between the age distribution of the LMC clusters and the field stars. Furthermore, it indicates that searches to find more clusters older than ~2.5 Gyr in the LMC are crucial to a better understanding of its global star formation history.

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Ata Sarajedini. 1998-04-30. Three Populous Clusters Discovered to be in the LMC Age Gap. https://arxiv.org/abs/astro-ph/9804340

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