Orbital variability and magnetic field of Centaurus X-3 with Suzaku
Abstract
Centaurus X-3 is a binary system consisting of an 4.8 s X-ray pulsar and an O-type supergiant. Suzaku observed the source over one full binary orbit of 2.1 days in 2008 December. The 1-10 keV XIS and 10-30 keV PIN lightcurves show high flux in the first half of the orbit and low flux interrupted by flares in the second half. Based on the hardness evolution, we selected three time intervals for spectra lanalysis in the range of 1-50 keV: a long, bright, relatively unabsorbed part during the first half of the orbit as well as the partially absorbed rise and the relatively unabsorbed peak of a flare in the second half. A thermal Comptonization model (compTT) provided a better description than different phenomenological cutoff powerlaw models. The long, bright part allowed for the best spectral state selected measurement of the cyclotron parameters so far, and led to a B-field value of 3.4 x 10^12 G. We compare this result to earlier measurements and discuss a possible luminosity dependence and its implication on source distance. The rise and peak of the flare were also well described by a thermal Comptonization continuum with additional partial covering absorption during the rise. We interpret this in terms of a clumpy wind structure. Future work includes pulse phase resolved spectroscopy, particularly of the cyclotron line, as well as spectral analysis of the low flux inter-flare spectra to check for indications of Compton scattering.
- Publication:
-
American Astronomical Society Meeting Abstracts #223
- Pub Date:
- January 2014
- Bibcode:
- 2014AAS...22315539G