| Issue |
A&A
Volume 435, Number 3, June I 2005
|
|
|---|---|---|
| Page(s) | 871 - 874 | |
| Section | Galactic structure, stellar clusters, and populations | |
| DOI | https://doi.org/10.1051/0004-6361:20042538 | |
| Published online | 13 May 2005 | |
Discovery of a stellar system in the background of 47 Tucanae
A new cluster of the Small Magellanic Cloud?
1
INAF - Osservatorio Astronomico di Bologna via Ranzani 1, 40127, Bologna, Italy e-mail: [michele.bellazzini;elena.pancino]@bo.astro.it
2
Università di Bologna, Dipartimento di Astronomia, via Ranzani 1, 40127, Bologna, Italy e-mail: francesco.ferraro3@unibo.it
Received:
14
December
2004
Accepted:
6
February
2005
We report on the discovery of a stellar system in the
background of the Galactic globular cluster 47 Tucanae (NGC 104),
located 
North-West of the cluster center. The object,
whose apparent diameter is 
, is partially resolved
into stars on the available CCD images, reaching a limiting magnitude
of 
, and is detected as a significant (more than 
) overdensity of blue stars (
). The color magnitude
diagram of the system, its characteristic projected size and its
position in the sky suggest that it is an intermediate-old age
cluster belonging to the Small Magellanic Cloud, whose outskirts lie
in the background of 47 Tuc. Although less likely, the
possibility that the object is an unknown dwarf galaxy in the
outskirts of the Local Group cannot completely be ruled out by the
present data.
Key words: Galaxy: globular clusters: individual: Bo A / galaxies: Local Group
© ESO, 2005
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