ASCA ’ s long look at the 288 millisecond radio pulsar , PSR J0631+1036 , reveals coherent X-ray pulsation from this source for the first time .
The source was first detected in the serendipitous Einstein observation and later identified as a radio pulsar .
Possible pulsation in the gamma-ray band has been detected from the CGRO EGRET data ( Zepka , et al .
1996 ) .
The X-ray spectrum in the ASCA band is characterized by a hard power-law type emission with a photon index \simeq 2.3 , when fitted with a single power-law function modified with absorption .
An additional blackbody component of kT \simeq 0.14 keV increases the quality of the spectral fit .
The observed X-ray flux is 2.1 \times 10 ^ { -13 } { ergs s ^ { -1 } cm ^ { -2 } } in the 1-10 keV band .
We find that many characteristics of PSR J0631+1036 are similar to those of middle-aged gamma-ray pulsars such as PSR B1055-52 , PSR B0633+17 ( Geminga ) , and PSR B0656+14 .