PSR J1420-6048, with a period of 68 ms, appears to be 13,000 years old. PSR J1837-0604, with a period of 96 ms, is estimated to be 34,000 years old. The increasing rotation periods observed for both pulsars indicates that they are losing energy at a significant rate. But three decades later many gamma-ray sources still defy identification. Seven gamma-ray sources near the Galactic plane have previously been identified as pulsars.
Pulsars are neutron stars formed in the collapse of massive stars in supernova explosions.
Although not yet complete, this survey is already the most successful survey for radio pulsars ever made, having found more than 600 previously unknown pulsars, nearly doubling the number previously found in 30 years of observations. The Parkes survey has found 30 radio pulsars with ages less than 100,000 years. With this encouragement the team plans to use the multibeam system to target more of these sources with even higher sensitivity and will expect to find many more gamma-ray emitting pulsars. If so, the nature of these mysterious galactic gamma-ray sources may soon be solved. Fernando Camilo is supported by NASA grant NAG 5-3229.