We report on the results of a new BeppoSAX (0.12-200 keV) observation of the peculiar X-ray binary source Circinus X-1 (Cir X-1) near the apastron. We produced a color-color diagram and selected seven different zones. We fitted the spectra obtained from each zone using a model consisting of a blackbody component, at a temperature of similar to 0.5 keV, and a Comptonized component, with a seed-photon temperature of similar to 1 keV, electron temperature of similar to 2.7 keV and optical depth of similar to 11. A soft excess between 0.6 keV and 0.9 keV is present in four out of the seven extracted spectra. To fit the soft excess we tried several continuum emission models, and we find good results only adding a further blackbody component absorbed by a different equivalent hydrogen column, an order of magnitude lower than the absorption of the other two components, its physical interpretation is however hard to address.

Presence of a soft excess between 0.6 keV and 0.9 keV in the energy spectrum of Cir X-1

BURDERI, LUCIANO;
2004-01-01

Abstract

We report on the results of a new BeppoSAX (0.12-200 keV) observation of the peculiar X-ray binary source Circinus X-1 (Cir X-1) near the apastron. We produced a color-color diagram and selected seven different zones. We fitted the spectra obtained from each zone using a model consisting of a blackbody component, at a temperature of similar to 0.5 keV, and a Comptonized component, with a seed-photon temperature of similar to 1 keV, electron temperature of similar to 2.7 keV and optical depth of similar to 11. A soft excess between 0.6 keV and 0.9 keV is present in four out of the seven extracted spectra. To fit the soft excess we tried several continuum emission models, and we find good results only adding a further blackbody component absorbed by a different equivalent hydrogen column, an order of magnitude lower than the absorption of the other two components, its physical interpretation is however hard to address.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11584/32791
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