DISCOVERY OF AN X-RAY SOURCE COINCIDENT WITH THE SOFT GAMMA-RAY REPEATER-0525-66

ALTHOUGH gamma-ray bursters (GRBs) have been known for more than 20 ye ars, no source has ever been identified in its quiescent state which m ight provide clues to its nature. On the other hand, two of the three known soft gamma-ray repeaters (SGRs), which emit intermittent bursts of soft gamma-rays. seem to be associated with supernova remnants1,2, and the recent identification of X-rays from one of these, SGR1806 - 2 0, supports the suggestion that a pulsar inside the remnant is the sou rce of the gamma-rays3-5. Here we report X-ray observations of SGR0525 - 66, which has been associated previously with the supernova remnant N49 (ref. 1). We identify point-like emission from a source coinciden t with SGR0525 - 66, which suggests that it too is a pulsar. The pulsa r seems to be only about 5,000 years old and has a high transverse vel ocity of about 1,200 km s-1, and we predict that the plerion (the regi on of radio synchrotron emission surrounding the pulsar) will be betwe en 0.1 and 0.3 arcsec across. A high birth velocity has been estimated for the pulsar associated with SGR1806 - 20 also4, and this character istic may be related to the reason why only a very few pulsars become SGRs.