ASCA Detection of Pulsed X-Ray Emission from PSR J0631+1036

ASCA's long look at the 288 ms radio pulsar PSR J0631+1036 reveals coherent X-ray pulsation from this source for the first time. The source was first detected in a serendipitous Einstein observation and later identified as a radio pulsar. Possible pulsation in the γ-ray band has been detected in the Compton Gamma Ray Observatory EGRET data. The X-ray spectrum in the ASCA band is characterized by a hard power-law-type emission with a photon index of 2.3, when fitted with a single power-law function modified with absorption. An additional blackbody component of kT 0.14 keV increases the quality of the spectral fit. The observed X-ray flux is 2.1 × 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 γ-ray pulsars such as PSR B1055-52, PSR B0633+17 (Geminga), and PSR B0656+14.