IAFE   05512
INSTITUTO DE ASTRONOMIA Y FISICA DEL ESPACIO
Unidad Ejecutora - UE
artículos
Título:
Washington photometry of five star clusters in the Large Magellanic Cloud
Autor/es:
PIATTI, ANDRÉS E.; GEISLER, DOUG; SARAJEDINI, A.; GALLART, C.
Revista:
ASTRONOMY AND ASTROPHYSICS
Editorial:
EDP SCIENCES S A
Referencias:
Año: 2009 vol. 501 p. 585 - 593
ISSN:
0004-6361
Resumen:
We present CCD photometry in the Washington system C and T1 passbands  down to $T_{1}$ $\sim$ 22.5 in the fields of NGC\,1697, SL\,133, NGC\,1997, SL\,663, and OHSC\,28, five mostly unstudied star clusters in the LMC.} {Cluster radii were estimated from star counts in appropriate-sized boxes distributed throughout the entire observed fields.  We perform a detailed analysis of the field star contamination and derive  cluster colour-magnitude diagrams (CMDs). Based on the  best fits of isochrones computed by the Padova group to the ($T_1$,$C-T_1$) CMDs, the $\delta(T_1)$ index and the Standard Giant Branch procedure, we derive metallicities and ages for the five clusters. We combine our sample with clusters with ages and \mets on a similar scale and examine relationships between position in the LMC,  age and metallicity.} { With the exception of NGC\,1697  (age = 0.7 Gyr, [Fe/H] = 0.0 dex), the remaining four clusters are of intermediate-age (from 2.2 to 3.0 Gyr) and relatively metal-poor ([Fe/H] = -0.7 dex). The cluster and field age-metallicty realtions show evidence for a \met offset but do overlap, particularly on the upper envelope side of the clusterage-metallicity relation.} {We confirm previous results that clusters younger than $\sim$ 1 Gyr were formed during an outside-in process; this occurred after a burst of cluster formation that  took place mainly in the outer disk and peaked at $\sim$ 2 Gyr ago.