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

ANDRÉS E. PIATTI

ASTROPHYSICAL JOURNAL

IOP PUBLISHING LTD

Lugar: Londres; Año: 2017 vol. 846 p. 10 - 13

0004-637X

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 theinfluence of photometric errors, and Milky Way and Small Magellanic Cloud composite stellarpopulation contamination, we found that the cluster stellar density profile reaches anearly constant value from $sim$ 1.7$r_t$ outwards, which does not depend on the direction from thecluster´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 of47 Tuc is a halo- like nearly constant low density structure.