SWIFT X-RAY TELESCOPE OBSERVATIONS OF THE NOVA-LIKE CATACLYSMIC VARIABLES MV Lyr, BZ Cam, AND V592 Cas

We present a total of ~45 ks (3 x 15 ks) of Swift X-Ray Telescope (XRT) observations for three nonmagnetic nova-like (NL) cataclysmic variables (CVs; MV Lyr, BZ Cam, V592 Cas) in order to study characteristics of boundary layers (BLs) in CVs. The nonmagnetic NLs are found mostly in a state of high mass accretion rate ([> or =, slanted]1 x 10 super(-9) M sub([middot in circle]) yr super(-1)), and some show occasional low states. Using the XRT data, we find optically thin multiple-temperature cooling flow type emission spectra with X-ray temperatures (kT sub(max)) of 21-50 keV. These hard X-ray-emitting BLs diverge from simple isobaric cooling flows, indicating X-ray temperatures that are of virial values in the disk. In addition, we detect power-law emission components from MV Lyr and BZ Cam and plausibly from V592 Cas, which may be a result of the Compton scattering of the optically thin emission from the fast wind outflows in these systems and/or Compton upscattering of the soft disk photons.