Title:
X-ray spectral variation of the changing-look Seyfert galaxy SDSSJ1552+2737

Abstract:
We report our multi-wavelength study of one changing-look Seyfert galaxy 
SDSSJ1552+2737. It presents significant H$\alpha$ line variation 
in the three epochs spectroscopic observations on timescales of decade. 
Along with the H$\alpha$ line variation we also detected significant variations 
in infrared, optical, and X-ray. The X-ray emission detected in Chandra is around 
five times brighter than the one four years ago detected in Suzaku. 
Only moderate absorption detected in all the X-ray observations with 
${\rm N_{H}}$ of $\sim 10^{21} {\rm cm^{-2}}$. The amplitudes and 
timescales observed in optical and infrared are against the obscuration variation scenario. 
The X-ray spectra harden along with the increasing of X-ray emission. 
Our result provides direct evidence that for CL AGNs not only 
the optical spectral type changes, the X-ray spectral shape also presents transition.