INVESTIGADORES
PIATTI Andres Eduardo
artículos
Título:
Constraining the LMC cluster age gap: Washington photometry of NGC 2155 and SL 896 (LW 480)
Autor/es:
PIATTI, ANDRÉS E.; SARAJEDINI, A.; GEISLER, DOUG; BICA, EDUARDO; CLARIA OLMEDO, JUAN JOSÉ
Revista:
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Referencias:
Año: 2002 vol. 329 p. 556 - 566
ISSN:
0035-8711
Resumen:
We carried out Washington system photometry of the intermediate-age
Large Magellanic Cloud (LMC) star clusters NGC2155 and SL896 (LW480). We
derive ages and metallicities from the T1 versus
C-T1 colour-magnitude diagrams (CMDs). For the first time an
age has been obtained for SL896, 2.3+/-0.5Gyr. For NGC2155 we derive
3.6+/-0.7Gyr. The two clusters basically define the lower age limit of
the LMC age gap. In particular, NGC2155 is confirmed as the oldest
intermediate-age LMC cluster so far studied. The derived metallicities
are [Fe/H]=-0.9+/-0.2 and -0.6+/-0.2 for NGC2155 and SL896,
respectively. We also studied the CMDs of the surrounding fields, which
have a dominant turn-off comparable to that of the clusters themselves,
and similar metallicity, showing that one is dealing with an
intermediate-age disc where clusters and field stars have the same
origin. We inserted the present clusters in the LMC and Small Magellanic
Cloud (SMC) age-metallicity relations, using a set of homogeneous
determinations with the same method as in our previous studies, now
totalling 15 LMC clusters and four SMC clusters, together with some
additional values from the literature. The LMC and SMC age-metallicity
relations appear to be remarkably complementary, since the SMC was
actively star-forming during the LMC quiescent age gap epoch.