2001/07/03 by G. Ramsay, Gavin Ramsay, M. Cropper +7 · 3 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Pulsars and Gravitational Waves Research #astro-ph
paper · pdf · doi:10.1046/j.1365-8711.2001.04798.x
published as Mon.Not.Roy.Astron.Soc. 326 (2001) L27 · Accepted by MNRAS as a letter, 5 pages, 2 figures
arxiv created 2001/07/03 · openalex publication_date 2001/09/01 · arxiv updated 2009/12/01 · openalex created_date 2019/06/27 · openalex updated_date 2026/07/28
We present an analysis of the X-ray spectra of two strongly magnetic cataclysmic variables, DP Leo and WW Hor, made using XMM-Newton. Both systems were in intermediate levels of accretion. Hard optically thin X-ray emission from the shocked accreting gas was detected from both systems, while a soft blackbody X-ray component from the heated surface was detected only in DP Leo. We suggest that the lack of a soft X-ray component in WW Hor is owing to the fact that the accretion area is larger than in previous observations with a resulting lower temperature for the re-processed hard X-rays. Using a multi-temperature model of the post-shock flow, we estimate that the white dwarf in both systems has a mass greater than 1 M⊙. The implications of this result are discussed. We demonstrate that the ‘soft X-ray excess’ observed in many magnetic cataclysmic variables can be partially attributed to using an inappropriate model for the hard X-ray emission.