On the multiwavelength nature of magnetic cataclysmic variables

This thesis details multi-wavelength observations of two magnetic cataclysmic variables; the polar QQ Vulpeculae and the intermediate polar (IP) EX Hydrae. QQ Vul was the subject of a 150 ksec photometric observation with the EUVE Satellite. Due to an X-ray leak in one of the detectors, we in fact obtained simultaneous X-ray (λ_peak ∼ 44Å) and EUV (λ_peak = 89Å) data. The unique shape of the X-ray light curve provides evidence for two pole accretion. Detailed examination of the photometric data indicates that QQ Vul undergoes a stellar eclipse of the X-ray emitting region, indicative of a high binary inclination.; EX Hydrae was the subject of a large multi-wavelength campaign and here, observations from EUVE, HST, RXTE, and several ground based observatories are discussed. EUVE obtained 106 sec of photometry and spectroscopy. The high signal-to-noise observations present new results and challenge the current IP models. The magnetic field in EX Hya is likely strong enough (a few MG) to begin pulling material directly from the outer edge of the disk, thereby forming a large accretion curtain which would produce a very broad bulge dip. The RXTE and BV RI photometry is used to corroborate this model. Iron spectral line ratios give a temperature of log T(K) = 6.5–6.9 for all spin phases and a poorly constrained density of n_e = 1010–1011 cm−3 for the emitting plasma.; The six orbits of HST/STIS time-tagged, high resolution, ∼0.02Å/pixel, spectra provides an excellent opportunity to study the UV properties of EX Hya. An analysis of the narrow and broad emission lines present in the UV spectra show that the broad lines originate from the accretion curtains while the narrow components are formed close to the white dwarf surface. The continuum flux is analyzed by fitting theoretical accretion disk and white dwarf models created by TLUSTY and SYNSPEC to the UV spectra. It is found that EX Hya contains a white dwarf of mass 0.90 $M\odot$, an annular accretion disk truncated at 2.5 R _WD, and is at a distance of 60 pc.