  Gamma Cas and its dozen analogs comprise a small but distinct class of X-ray
sources. They are early Be-type stars with an exceptionally hard thermal X-ray
emission. The X-ray production mechanism has been under intense debate. Two
competing ideas are (i) the magnetic activities in the Be star and its disk and
(ii) the mass accretion onto the unidentified white dwarf (WD). We adopt the
latter as a working hypothesis and apply physical models developed to describe
the X-ray spectra of classical WD binaries containing a late-type companion.
Models of non-magnetic and magnetic accreting WDs were applied to gamma Cas and
its brightest analog HD110432 using the Suzaku and NuSTAR data. The spectra
were fitted by the two models, including the Fe I fluorescence and the Compton
reflection in a consistent geometry. The derived physical parameters, such as
the WD mass and mass accretion rate, are in a reasonable range in comparison to
their classical WD binary counterparts. Additional pieces of evidence in the
X-ray spectra (partial covering, Fe L lines, and Fe I fluorescence) were not
conclusive enough to classify these two sources into a sub-class of accreting
WD binaries. We discuss further observations, especially long-term temporal
behaviors, which are important to elucidate the nature of these sources more if
indeed they host accreting WDs.
