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dc.contributor.authorBica, Eduardo Luiz Damianipt_BR
dc.contributor.authorGeisler, Dougpt_BR
dc.contributor.authorDottori, Horacio Albertopt_BR
dc.contributor.authorClaria Olmedo, Juan Josept_BR
dc.contributor.authorPiatti, Andres E.pt_BR
dc.contributor.authorSantos Junior, Joao Francisco Coelho dospt_BR
dc.date.accessioned2014-12-04T02:13:47Zpt_BR
dc.date.issued1998pt_BR
dc.identifier.issn0004-6256pt_BR
dc.identifier.urihttp://hdl.handle.net/10183/107736pt_BR
dc.description.abstractWe present Washington system CT1 color-magnitude diagrams of 13 star clusters and their surrounding fields that lie in the outer parts of the LMC disk (r>4°), as well as a comparison inner cluster. The total area covered is large (2/3 deg²), allowing us to study the clusters and their fields individually and in the context of the entire Galaxy. Ages are determined by means of the magnitude difference δT1 between the giant branch clump and the turnoff, while metallicities are derived from the location of the giant and subgiant branches as compared with fiducial star clusters. This yields a unique data set in which ages and metallicities for both a significant sample of clusters and their fields are determined homogeneously. We find that in most cases the stellar population of each star cluster is quite similar to that of the field where it is embedded, sharing its mean age and metallicity. The old population (t≥10 Gyr) is detected in most fields as a small concentration of stars on the horizontal branch blueward and faintward of the prominent clump. Three particular Ðelds present remarkable properties : (1) The thus-far unique cluster ESO 121-SC03 at ≈ 9 Gyr has a surrounding field that shares the same properties (which, in turn, is also unique, in that such a dominant old-field component is not present elsewhere−at least not significantly in the fields as yet studied). The field surrounding the far eastern intermediate-age cluster OHSC 37 is noteworthy in that we do not detect any evidence of LMC stars : it is essentially a Galactic foreground field. We can thus detect the LMC field out to greater than 11° (the deprojected distance of ESO 121- SC03), or ~ 11 kpc, but not to 13° (~13 kpc), despite the presence of clusters at this distance. (3) In the northern part of the LMC disk, the fields of SL 388 and SL 509 present color-magnitude diagrams with a secondary clump ≈0.45 mag fainter than the dominant intermediate-age clump, suggesting a stellar population component located behind the LMC disk at a distance comparable to that of the SMC. Possibly we are witnessing a depth effect in the LMC, and the size of the corresponding structure is comparable to the size of a dwarf galaxy. The unusual spatial location of the cluster OHSC 37 and the anomalous properties of the SL 388 and SL 509 fields might be explained as debris from previous LMC interactions with the Galaxy and/or the SMC. The mean metallicity derived for the intermediate-age outer disk clusters is ‹[Fe/H]› = -0.66, and for their surrounding fields ‹[Fe/H]› = -0.56. These values are significantly lower than those found by Olszewski et al. for a sample of clusters of similar age but are in good agreement with several recent studies. A few clusters stand out in the age-metallicity relation, in that they are intermediate-age clusters at relatively low metallicity ([Fe/H]≈ -1).en
dc.format.mimetypeapplication/pdf
dc.language.isoengpt_BR
dc.relation.ispartofThe astronomical journal. New York. Vol. 116, no. 2 (Aug. 1998), p. 723-737pt_BR
dc.rightsOpen Accessen
dc.subjectGrande Nuvem de Magalhãespt_BR
dc.subjectGalaxies : star clustersen
dc.subjectMagellanic cloudsen
dc.subjectAglomerados estelares e associacoespt_BR
dc.subjectEvolucao estelarpt_BR
dc.titleAges and metallicities of star clusters and surrounding fiels in the outer disk of the Large Magellanic Cloudpt_BR
dc.typeArtigo de periódicopt_BR
dc.identifier.nrb000224231pt_BR
dc.type.originEstrangeiropt_BR


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