R. Droulans | Searcharxiv

arXiv2013

The X-ray spectro-timing properties of a major radio flare episode in Cygnus X-3

We have performed a principal component analysis on the X-ray spectra of the microquasar Cygnus X-3 from RXTE, INTEGRAL and Swift during a major flare ejection event in 2006 May-July. The analysis showed that there are two main variability components in play, i.e. two principal components explained almost all the variability in the X-ray lightcurves. According to the spectral shape of these components and spectral fits to the original data, the most probable emission components corresponding to the principal components are inverse-Compton scattering and bremsstrahlung. We find that these components form a double-peaked profile when phase-folded with the peaks occurring in opposite phases. This could be due to an asymmetrical wind around the companion star with which the compact object is interacting.

astro-ph.HE↗

arXiv2012

2006 May-July Major Radio Flare episodes in Cygnus X-3: spectro-timing analysis of the X-ray data

We analyse in detail the X-ray data of the microquasar Cygnus X-3 obtained during major radio flaring episodes in 2006 with multiple observatories. The analysis consists of two parts: probing the fast (~ 1 minute) X-ray spectral evolution with Principal Component Analysis followed by subsequent spectral fits to the time-averaged spectra (~ 3 ks). Based on the analysis we find that the overall X-ray variability during major flaring episodes can be attributed to two principal components whose evolution based on spectral fits is best reproduced by a hybrid Comptonization component and a bremsstrahlung or saturated thermal Comptonization component. The variability of the thermal component is found to be linked to the change in the X-ray/radio spectral state. In addition, we find that the seed photons for the Comptonization originate in two seed photon populations that include the additional thermal emission and emission from the accretion disc. The Comptonization of the photons from the thermal component dominates, at least during the major radio flare episode in question, and the Comptonization of disc photons is intermittent and can be attributed to the phase interval 0.2-0.4. The most likely location for Comptonization is in the shocks in the jet.

astro-ph.HE↗