Be star candidates in the Large Magellanic Cloud: the catalogue and comparison with the Small Magellanic Cloud sample |
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Authors: | B. E. Sabogal,R. E. Mennickent,G. Pietrzy ski, W. Gieren |
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Affiliation: | Instituto de Astrofísica de Andalucía, CSIC, Apdo. Correos 3004, E-18080 Granada, Spain;Departamento de Astronomía y Astrofísica, Universidad de Valencia, E-46100 Burjassot, Spain;Stockholm Observatory, AlbaNova, Roslagstullsbacken 21, SE-10691 Stockholm, Sweden;Harvard-Smithsonian Center for Astrophysics, 60 Garden St MS 51, Cambridge, MA 02138, USA;Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany;Departamento de Física Teórica y del Cosmos, Universidad de Granada, E-18071 Granada, Spain;Naval Research Laboratory, Code 7213, Washington, DC 20375-5320, USA |
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Abstract: | We present a catalogue with coordinates and photometric data of 2446 Be star candidates in the Large Magellanic Cloud (LMC), based on a search of the OGLE II data base. The I -band light curves of these stars show outbursts in 24 per cent of the sample (Type-1 stars), high and low states in 10 per cent, periodic variations in 6 per cent (Type-3 stars), and stochastic variations in 60 per cent of the cases. We report on the result of the statistical study of light curves of Type-1 and Type-3 stars in the LMC, and the comparison with the previously reported results of the Small Magellanic Cloud (SMC) sample. We find a statistically significant difference between amplitude, duration and asymmetry distributions of outbursts in both galaxies. Outbursts of SMC Type-1 stars are usually brighter, longer and with a slower decline. We find a bimodal distribution of periods of Type-3 stars in both galaxies, probably related to the recently discovered double periodic blue variables. We find also period and amplitude distributions of Type-3 LMC stars statistically different from those of the SMC stars. Our findings above suggest that the mechanisms causing the observed photometric variability of Type-1 and Type-3 stars could depend on metallicity. Moreover, they suggest that the outbursts are not primarily caused by stellar winds. |
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Keywords: | supernovae: individual: SN 2001gd galaxies: individual: NGC 5033 radio continuum: stars X-rays: individual SN 2001gd |
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