SIMBAD references

We report on XMM-Newton observations of the magnetic CV AE Aqr. High-resolution spectroscopy of the He-like triplet of N and O with the RGS has enabled us to measure the electron number density of the plasma as ∼10¹¹/cm3. Incorporating this with the emission measure, we estimate the geometrical scale of the plasma emitting these lines to be l_p≃(2-3)x10¹⁰ cm. Since the density and the scale are both incompatible with the standard postshock accretion column of an mCV, the plasma cannot be a product of mass accretion onto the white dwarf. The widths of the H-like Kα emission lines of N and O (=1250-1600 km/s) are of similar magnitude to the thermal velocity dispersion of the hottest part of the plasma, where kT_maxis 4.6 keV. It is known that Balmer series and UV emission lines also show a similar velocity dispersion. In addition, like these lines, the X-ray emission lines are found to show dramatic flaring activity. These facts strongly suggest that all these broad emission lines from X-ray to optical wave bands are produced in the course of adiabatic cooling of the plasma once heated up to T_max in the deep gravitational potential of the white dwarf. This interpretation can resolve the problem of the absence of the high-velocity component in the Hα emission line spectrum by a scenario where the plasma that is expelled due to the propeller action is still too hot to emit the Hα line within a region of r<l_p(roughly equal to the Roche lobe size) from the white dwarf where the high-velocity component is expected to originate.