6533b7cefe1ef96bd125723a
RESEARCH PRODUCT
Presence of a soft excess between 0.6 keV and 0.9 keV in the energy spectrum of Cir X-1
R. IariaM. Van Der KlisN. R. RobbaLuciano BurderiLuigi StellaM. SpanòT. Di SalvoT. Di SalvoF. Fronterasubject
PhysicsNuclear and High Energy PhysicsHydrogenAstrophysics::High Energy Astrophysical PhenomenaBinary numberchemistry.chemical_elementAstrophysicsAtomic and Molecular Physics and OpticsSpectral linechemistryEnergy spectrumElectron temperatureCircinusBlack-body radiationOrder of magnitudedescription
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 ∼0.5 keV, and a Comptonized component, with a seed-photon temperature of ∼1 keV, electron temperature of ∼2.7 keV and optical depth of ∼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.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2004-06-01 |