THE XMM-NEWTON /EPIC X-RAY LIGHT CURVE ANALYSIS OF WR 6

• Main Authors: Ignace, R. (Author), Gayley, K. G. (Author), Hamann, W.-R (Author), Huenemoerder, David P. (Contributor), Oskinova, Lidia M. (Author), Pollock, A. M. T. (Author), McFall, M. (Author)
• Other Authors: MIT Kavli Institute for Astrophysics and Space Research (Contributor)
• Format: Article
• Language: English
• Published: Institute of Physics/American Astronomical Society, 2015-02-04T18:54:04Z.
• Subjects: Article
• Online Access: Get fulltext

We obtained four pointings of over 100 ks each of the well-studied Wolf-Rayet star WR 6 with the XMM-Newton satellite. With a first paper emphasizing the results of spectral analysis, this follow-up highlights the X-ray variability clearly detected in all four pointings. However, phased light curves fail to confirm obvious cyclic behavior on the well-established 3.766 day period widely found at longer wavelengths. The data are of such quality that we were able to conduct a search for event clustering in the arrival times of X-ray photons. However, we fail to detect any such clustering. One possibility is that X-rays are generated in a stationary shock structure. In this context we favor a corotating interaction region (CIR) and present a phenomenological model for X-rays from a CIR structure. We show that a CIR has the potential to account simultaneously for the X-ray variability and constraints provided by the spectral analysis. Ultimately, the viability of the CIR model will require both intermittent long-term X-ray monitoring of WR 6 and better physical models of CIR X-ray production at large radii in stellar winds.
United States. National Aeronautics and Space Administration (Smithsonian Astrophysical Observatory contract SV3-73016, Chandra X-Ray Center and Science Instruments)
German Aerospace Center (DLR) (grant 50 OR 1302)