  We report an X-ray study of the evolved Galactic supernova remnant (SNR)
G156.2+5.7 based on six pointing observations with Suzaku. The remnant's large
extent (100$\arcmin$ in diameter) allows us to investigate its radial structure
in the northwestern and eastern directions from the apparent center. The X-ray
spectra were well fit with a two-component non-equilibrium ionization model
representing the swept-up interstellar medium (ISM) and the metal-rich ejecta.
We found prominent central concentrations of Si, S and Fe from the ejecta
component; the lighter elements of O, Ne and Mg were distributed more
uniformly. The temperature of the ISM component suggests a slow shock (610-960
km s$^{-1}$), hence the remnant's age is estimated to be 7,000-15,000 yr,
assuming its distance to be $\sim$1.1 kpc. G156.2+5.7 has also been thought to
emit hard, non-thermal X-rays, despite being considerably older than any other
such remnant. In response to a recent discovery of a background cluster of
galaxies (2XMM J045637.2+522411), we carefully excluded its contribution, and
reexamined the origin of the hard X-ray emission. We found that the residual
hard X-ray emission is consistent with the expected level of the cosmic X-ray
background. Thus, no robust evidence for the non-thermal emission was obtained
from G156.2+5.7. These results are consistent with the picture of an evolved
SNR.
