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Ýlgili Makaleler
A Revised and Extended Catalog of Magellanic System Clusters, Associations, and Emission Nebulae. II. The Large Magellanic Cloud
A survey of extended objects in the Large Magellanic Cloud was carriedout on the ESO/SERC R and J Sky Survey Atlases, checking entries inprevious catalogs and searching for new objects. The census provided6659 objects including star clusters, emission-free associations, andobjects related to emission nebulae. Each of these classes containsthree subclasses with intermediate properties, which are used to infertotal populations. The survey includes cross identifications amongcatalogs, and we present 3246 new objects. We provide accuratepositions, classification, and homogeneous measurements of sizes andposition angles, as well as information on cluster pairs andhierarchical relation for superimposed objects. This unification andenlargement of catalogs is important for future searches of fainter andsmaller new objects. We discuss the angular and size distributions ofthe objects of the different classes. The angular distributions show twooff-centered systems with different inclinations, suggesting that theLMC disk is warped. The present catalog together with its previouscounterpart for the SMC and the inter-Cloud region provide a totalpopulation of 7847 extended objects in the Magellanic System. Theangular distribution of the ensemble reveals important clues on theinteraction between the LMC and SMC.
| Planetary nebulae associated with star clusters in the LMC.
The catalogues of LMC clusters and PN both based on surveys of UKSchmidt Telescope plates were searched to identify those PN that arefound near to cluster centres and could be genuine cluster members.Statistical tests were carried out to study chance superpositioneffects. For a number of clusters which were bright enough, spectralclassification of individual stars was carried out on objective-prismplates taken with the UK Schmidt Telescope, in order to trace M- andC-stars which are believed to be PN progenitors. There are 48 clusterswith PNs close enough to be actual cluster members. Various testssuggest that about half of these are expected to belong to the clusters.
| Integrated UBV Photometry of 624 Star Clusters and Associations in the Large Magellanic Cloud
We present a catalog of integrated UBV photometry of 504 star clustersand 120 stellar associations in the LMC, part of them still embedded inemitting gas. We study age groups in terms of equivalent SWB typesderived from the (U-B) X (B-V) diagram. The size of the spatialdistributions increases steadily with age (SWB types), whereas adifference of axial ratio exists between the groups younger than 30 Myrand those older, which implies a nearly face-on orientation for theformer and a tilt of ~45^deg^ for the latter groups. Asymmetries arepresent in the spatial distributions, which, together with thenoncoincidence of the centroids for different age groups, suggest thatthe LMC disk was severely perturbed in the past.
| The cluster system of the Large Magellanic Cloud
A new catalog of clusters in the Large Magellanic Cloud has beenconstructed from searches of the IIIa-J component of the ESO/SERCSouthern Sky Atlas. The catalog contains coordinate and diametermeasurements of 1762 clusters in a 25 deg x 25 deg area of sky centeredon the LMC, but excluding the very crowded 3.5 sq deg region around theBar. The distribution of these clusters appears as two superimposedelliptical systems. The higher density inner system extends over about 8deg; the lower density outer system can be represented by a 13 deg x 10deg disk inclined at 42 deg to the line of sight. There are suggestionsof two weak 'arms' in the latter.
| Distribution of spectral types in the LMC clusters
The distribution of spectral types in 42 LMC globular star clusterscovering all evolutionary ages was determined using objective prismspectra taken with the 1.2-m U.K. Schmidt Telescope in Australia. Thederived spectral type distributions show that the clusters can bedivided into five age categories from about 10 to the 7th to more than10 to the 9th yr. Several clusters were found to contain carbon starswith C/M ratios ranging from 0.07 to 0.4. These ratios were comparedwith those found for the SMC clusters and the Milky Way. It was foundthat the stars of the LMC exhibit a smaller range of C/M ratios than inthe SMC, but larger than in the Galaxy, thus providing an additionaltest of the theoretical models predicting a correlation between the C/Mratio and metal content. It was also found that the majority of youngclusters were embedded in older fields, while the intrmediate clusterswere embeded in younger fields, and the remote old clusters wereembedded in a stellar content of similar age.
| Spectral classification of bright stars in LMC clusters. II
Spectral classification catalogs and their identification charts for tendisk LMC globular clusters and their adjoining fields are given. Theclusters range from very young to old and are located in various placesoutside the bar of the galaxy. For this project, film copies of the1.2-m UK Schmidt prism plates were examined in the Athens Observatory bymeans of a binocular microscope. All the stars classified in eachcluster are brighter than V = about 17.5 mag and located within thecluster's tidal radius.
| Observed dynamical parameters of the disk clusters of the LMC. I
A study of the observed dynamical parameters of 32 globular clusters ofthe LMC disk has been carried out by means of star counts. The clusterswere measured on a set of three plates (J, V, I) taken with the 1.2 mU.K. Schmidt Telescope. The derived tidal radii were all found to belarge within a very narrow range. As a consequence the range of thetotal masses was found to be very narrow as well. These two parametersare large in comparison to those of the disk young clusters of thegalaxy but they are similar to the dimensions of the halo galacticglobulars.
| A Catalogue of Clusters in The LMC
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