A weakening Compton hump and soft X-ray excess detected in the Seyfert-1
  galaxy MCG-02-58-22
  We have carried out an extensive X-ray spectral study of the bare Seyfert-1
galaxy MCG--02--58--22 to ascertain the nature of the X-ray reprocessing media,
using observations from Suzaku (2009) and simultaneous observations from
XMM-Newton and NuSTAR (2016) . The most significant results of our
investigation are: 1. The primary X-ray emission from the corona is constant in
these observations, both in terms of the power law slope ($\Gamma=1.80$) and
luminosity ($L_{2-10 \rm keV}= 2.55\times 10^{44} $ erg/s). 2. The soft excess
flux decreased by a factor of two in 2016, the Compton hump weakened/vanished
in 2016, and the narrow FeK$\alpha$ emission line became marginally broad
($\sigma=0.35\pm0.08$ keV) and its flux doubled in 2016. 3. From physical model
fits we find that the normalization of the narrow component of the FeK$\alpha$
line does not change in the two epochs, although the Compton hump vanishes in
the same time span. Since the primary X-ray continuum does not change, we
presume that any changes in the reprocessed emission must arise due to changes
in the reprocessing media. Our primary conclusions are: A. The vanishing of the
Compton hump in 2016 can probably be explained by a dynamic clumpy torus which
is infalling/outflowing, or by a polar torus wind. B. The torus in this AGN
possibly has two structures: an equatorial toroidal disk (producing the narrow
FeK$\alpha$ emission) and a polar component (producing the variable Compton
hump), C. The reduction of the soft-excess flux by half and increase in the
FeK$\alpha$ flux by a factor of two in the same period cannot be adequately
explained by ionized disk reflection model alone.
