NuSTAR and Swift Observations of the Fast Rotating Magnetized White Dwarf AE Aquarii

AE Aquarii is a cataclysmic variable with the fastest known rotating magnetized white dwarf (P _spin = 33.08 s). Compared to many intermediate polars, AE Aquarii shows a soft X-ray spectrum with a very low luminosity (L _X ~ 10³¹ erg s^-1). We have analyzed overlapping observations of this system with the NuSTAR and the Swift X-ray observatories in 2012 September. We find the 0.5-30 keV spectra to be well fitted by either an optically thin thermal plasma model with three temperatures of 0.75^{+0.18}_{-0.45}, 2.29^{+0.96}_{-0.82}, and 9.33^{+6.07}_{-2.18} keV, or an optically thin thermal plasma model with two temperatures of 1.00^{+0.34}_{-0.23} and 4.64^{+1.58}_{-0.84} keV plus a power-law component with photon index of 2.50^{+0.17}_{-0.23}. The pulse profile in the 3-20 keV band is broad and approximately sinusoidal, with a pulsed fraction of 16.6% ± 2.3%. We do not find any evidence for a previously reported sharp feature in the pulse profile.