Wang, MY;
Koposov, S;
Drlica-Wagner, A;
Pieres, A;
Li, TS;
de Boer, T;
Bechtol, K;
... Walker, AR; + view all
(2019)
Rediscovery of the Sixth Star Cluster in the Fornax Dwarf Spheroidal Galaxy.
Astrophysical Journal Letters
, 875
, Article L13. 10.3847/2041-8213/ab14f5.
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Abstract
Since first noticed by Shapley in 1939, a faint object coincident with the Fornax dwarf spheroidal has long been discussed as a possible sixth globular cluster (GC) system. However, debate has continued over whether this overdensity is a statistical artifact or a blended galaxy group. In this Letter we demonstrate, using deep DECam imaging data, that this object is well resolved into stars and is a bona fide star cluster. The stellar overdensity of this cluster is statistically significant at the level of ~6–6.7σ in several different photometric catalogs including Gaia. Therefore, it is highly unlikely to be caused by random fluctuation. We show that Fornax 6 is a star cluster with a peculiarly low surface brightness and irregular shape, which may indicate a strong tidal influence from its host galaxy. The Hess diagram of Fornax 6 is largely consistent with that of Fornax field stars, but it appears to be slightly bluer. However, it is still likely more metal-rich than most of the GCs in the system. Faint clusters like Fornax 6 that orbit and potentially get disrupted in the centers of dwarf galaxies can prove crucial for constraining the dark matter distribution in Milky Way satellites.
| Type: | Article |
|---|---|
| Title: | Rediscovery of the Sixth Star Cluster in the Fornax Dwarf Spheroidal Galaxy |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3847/2041-8213/ab14f5 |
| Publisher version: | https://doi.org/10.3847/2041-8213/ab14f5 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | galaxies: star clusters: general |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10074127 |
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