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Astron. Astrophys. 358, 144-153 (2000)
Studies of binary star cluster candidates in the bar of the LMC
I. SL 353 and SL 349 *
A. Dieball 1,
E.K. Grebel ** 2 and
C. Theis 3
1 Sternwarte der Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany
2 University of Washington, Department of Astronomy, Box 351580, Seattle, WA 98195-1580, USA
3 Institut für Theoretische Physik und Astrophysik der Universität Kiel, 24098 Kiel, Germany
Received 22 December 1999 / Accepted 27 March 2000
Abstract
We present a detailed study of the cluster pair SL 353 &
SL 349. This candidate binary cluster is located at the northwestern
rim of the LMC bar. Based on photometric data we find that both
clusters are coeval with an age of
550![[FORMULA]](img1.gif)
100 Myr. We use the Ca II triplet
in the spectra of individual red giants to derive radial velocities.
Both components of the binary cluster candidate show very similar mean
velocities
(![[FORMULA]](img2.gif)
km ![[FORMULA]](img3.gif)
for SL 349 and
![[FORMULA]](img4.gif)
km
for SL 353) while the field stars show lower velocities
(![[FORMULA]](img5.gif)
km ).
These findings suggest a common origin of the two clusters from the
same GMC. In this sense the cluster pair may constitute a true binary
cluster. We furthermore investigate the stellar densities in and
around the star clusters and compare them with isopleths created from
artificial, interacting as well as non-interacting star clusters.
Gravitational interaction leads to a distortion which can also be
found in the observed pair.
Key words: stars:
Hertzsprung 
Russel (HR) and C-M
diagrams
stars:
kinematics
galaxies: clusters: individual: SL 353, individual:
SL 349
galaxies: Magellanic Clouds
* Based on observations taken at the European Southern Observatory, La Silla, Chile.
** Hubble fellow
Send offprint requests to: A. Dieball (adieball@astro.uni-bonn.de)
Contents
- 1. Introduction
- 2. Photometric observations and data reduction
- 3. Stellar density maps
- 4. Colour magnitude diagrams and isochrone fitting
- 5. Spectroscopic data and their reduction
- 6. Radial velocities
- 7. N-body simulations
- 8. Summary and conclusions
- Acknowledgements
- References
© European Southern Observatory (ESO) 2000
Online publication: June 26, 2000
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