6533b85afe1ef96bd12b8cd1
RESEARCH PRODUCT
Broad-band Spectral Evolution of Scorpius X-1 along its Color-Color Diagram
G. LavagettoP. T. ZyckiA. D'aiT. Di SalvoR. IariaN. R. Robbasubject
individual (Scorpius X-1); stars : neutron; X-rays : binaries; X-rays : general; X-rays : stars [accretion accretion disks; stars]PhysicsAccretion (meteorology)Component (thermodynamics)Astrophysics::High Energy Astrophysical PhenomenaX-rays : starsDiagramAstrophysics (astro-ph)FOS: Physical sciencesstars : individual (Scorpius X-1)Astronomy and AstrophysicsColor–color diagramPlasmaAstrophysicsAstrophysicsaccretion accretion diskstars : neutronSpectral lineSpace and Planetary ScienceThermalX-rays : binarieElectronic band structureAstrophysics::Galaxy AstrophysicsX-rays : generaldescription
We analyze a large collection of RXTE archive data from April 1997 to August 2003 of the bright X-ray source Scorpius X-1 in order to study the broadband spectral evolution of the source for different values of the inferred mass accretion rate by studying energy spectra from selected regions in the Z-track of its Color-Color Diagram. A two-component model, consisting of a soft thermal component interpreted as thermal emission from an accretion disk and a thermal Comptonization component, is unable to fit the whole 3--200 keV energy spectrum at low accretion rates. Strong residuals in the highest energy band of the spectrum require the addition of a third component that can be fitted with a power-law component, that could represent a second thermal Comptonization from a much hotter plasma, or a hybrid thermal/non-thermal Comptonization. We discuss the physical implications derived from the results of our analysis, with a particular emphasis on the hardest part of the X-ray emission and its possible origins.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2007-05-29 |