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arXiv · 1708.06194

Detection of a diffuse extended halo-like structure around 47 Tuc

Andrés E. Piatti
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Abstract

We constructed for the first time a stellar density profile of 47 Tucanae (47 Tuc) out of $\sim$ 5.5 times its tidal radius ($r_t$) using high-quality deep $BV$ photometry. After carefully considering the influence of photometric errors, and Milky Way and Small Magellanic Cloud composite stellar population contamination, we found that the cluster stellar density profile reaches a nearly constant value from $\sim$ 1.7$r_t$ outwards, which does not depend on the direction from the cluster's center considered. These results visibly contrast with recent distinct theoretical predictions on the existence of tidal tails or on a density profile that falls as $r^{-4}$ at large distances, and with observational outcomes of a clumpy structure as well. Our results suggest that the envelope of 47 Tuc is a halo- like nearly constant low density structure.

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Andrés E. Piatti. 2017-08-21. Detection of a diffuse extended halo-like structure around 47 Tuc. https://doi.org/10.3847/2041-8213/aa8773

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