EUVE Observations of Polars

J. Warren

Cape Workshop on Magnetic Cataclysmic Variables, ASP Conference Series, Col. 85, 1995. ed. D.A.H. Buckley and B. Warner.

Abstract

Polars are strong extreme ultraviolet (EUV) and soft X-ray (SXR) emitters. Virtually all of the EUV/SXR radiation emerges from the accretion spot (or arc in some systems) located near on or both of the magnetic poles of the white dwarf. The Extreme Ultraviolet Observer (EUVE) has as one of its bandpasses precisely the region occupied by the component, which allows EUVE a direct, relatively uncontaminated, view of the accretion region(s). EUVEis presently performing photometry and spectroscopy of several polars. EUV photometry is being used to address the geometry (angular size and vertical extent) of the accretion spot, and to observe the accretion column in absorption, both at the threading region and near the accretion spot. In the continuum, EUV spectroscopy is enabling tighter constraints to be placed on the temperature of the reprocessed photospheric component and the interstellar column, and line diagnostics are enabling detailed analysis of the emission and absorption physics. We present preliminary EUV photometric and spectral results of some of the brightest and/or most extensively covered (by EUVE) polars; namely UZ For, VV Pup, AM Her, and RE 1149+28

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