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An XMM-Newton observation of the nova-like variable UX UMa: spatially and spectrally resolved two-component X-ray emission

G. W. Pratt·K. Mukai·B. J. M. Hassall·T. Naylor·J. H. Wood
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Abstract

In the optical and ultraviolet regions of the electromagnetic spectrum, UX Ursae Majoris is a deeply eclipsing cataclysmic variable. However, no soft X-ray eclipse was detected in ROSAT observations. We have obtained a 38 ksec XMM-Newton observation to further constrain the origin of the X-rays. The combination of spectral and timing information allows us to identify two components in the X-ray emission of the system. The soft component, dominant below photon energies of 2 keV, can be fitted with a multi-temperature plasma model and is uneclipsed. The hard component, dominant above 3 keV, can be fitted with a kT ~ 5 keV plasma model and appears to be deeply eclipsed. We suggest that the most likely source of the hard X-ray emission in UX UMa, and other systems in high mass transfer states, is the boundary layer.

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G. W. Pratt, K. Mukai, B. J. M. Hassall, T. Naylor, J. H. Wood. 2004-01-10. An XMM-Newton observation of the nova-like variable UX UMa: spatially and spectrally resolved two-component X-ray emission. https://doi.org/10.1111/j.1365-2966.2004.07574.x

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