The XMM-Newton view of the X-ray spectrum of WR140 across periastron passage
Department of Astrophysics, Geophysics and Oceanography, University of Liège, Belgium, and Observatoire de Haute-Provence, Saint-Michel l’Observatoire, France
Department of Physics and Astronomy, University of Leeds, UK
Institute for Astronomy, Royal Observatory, Edinburgh, UK
Abstract
An XMM-Newton campaign dedicated to the study of the X-ray emission of the colliding wind massive binary WR140 across its 2009 periastron passage has been undertaken. The high quality EPIC spectra revealed a strong phase-locked variability both in flux and in spectral shape. The observed variations are consistently explained by the varying emission measure of the emitting plasma along the eccentric orbit, and by the changing absorption column density along the line of sight. Our results are first interpreted in the context of simple multi-temperature thermal emission models, and prospects for more sophisticated modeling are discussed.