We report here on the observation of Kes 27 , a proto-typical mixed-morphology SNR , using ASCA .
It clearly shows a filled-center structure in the X-ray region while a shell structure in the radio region .
There are two radio bright regions : one is in the center , while the other is in the east rim .
The X-ray intensity peak coincides well with the radio bright region at the center .
The X-ray spectrum was well-fitted by a collisional ionization equilibrium model with solar abundances .
Taking into account the ionization parameter ( > 10 ^ { 12 } ~ { } cm ^ { -3 } s ) and the plasma density ( 0.39 ^ { +0.03 } _ { -0.02 } ~ { } cm ^ { -3 } ) , we found that the age of the SNR is longer than 8 \times 10 ^ { 4 } yr .
The hardness ratio map indicates that the inner region shows a harder spectrum than that in the outer region , which does not come from the heavier interstellar absorption feature , but from the higher temperature .
There is a temperature gradient from the innner region ( 0.84 \pm 0.08 keV ) toward outer region ( 0.59 ^ { +0.04 } _ { -0.06 } keV ) , indicating that the thermal conduction does not play an important role .