We report results of Swift observations for the high mass Be/X-ray binarysystem 1A 1118-615, during an outburst stage in January, 2009 and at a flaringstage in March, 2009. Using the epoch-folding method, we successfully detecteda pulsed period of 407.69(2) sec in the outburst of January and of 407.26(1)sec after the flare detection in March. We find that the spectral detection forthe source during outburst can be described by a blackbody model with a hightemperature (kT ~ 1-3 keV) and a small radius (R ~ 1 km), indicating that theemission results from the polar cap of the neutron star. On the other hand, thespectra obtained after the outburst can further be described by adding anadditional component with a lower temperature (kT ~ 0.1-0.2 keV) and a largeremission radius (R ~ 10-500 km), which indicates the emission from around theinner region of an accretion disk. We find that the thermal emission from thehot spot of the accreting neutron star dominates the radiation in outburst; theexistence of both this X-ray contribution and the additional soft componentsuggest that the polar cap and the accretion disk emission might co-exist afterthe outburst. Because the two-blackbody signature at the flaring stage is aunique feature of 1A 1118-615, our spectral results may provide a new insightto interpret the X-ray emission for the accreting neutron star. The timeseparation between the three main outbursts of this system is ~17 years and itmight be related to the orbital period. We derive and discuss the associatedphysical properties by assuming the elongated orbit for this specific Be/X-raytransient.
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