A SUPERNOVA REMNANT ASSOCIATED WITH THE YOUNG GAMMA-RAY PULSAR PSR1706-44

THE Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory satellite recently detected1 pulsed gamma-radiation from the radio pulsar PSR1706-44; this is only the fourth radio pulsar to be identified as a gamma-ray source. The other three (Vela, the Crab and PSR1509-58) are all associated with supernova remnants (SNRs), whereas very few-perhaps four-of the remaining 500 or so galactic radio pulsars have convincing associations with SNRs2. We have mapped the field around PSR1706-44 at 843 M Hz with a resolution of 44 arcsec using the Molonglo Observatory Synthesis Telescope, and have identified a shell-type SNR at a distance of about 3 kpc-consistent with the distance deduced for the pulsar. The pulsar is seen as a slightly variable point source, located in an enhanced knot on the arc of the SNR shell.