The pulsating nature comes from the rapid rotation of the neutron star whose magnetic field axis is not aligned with its spin axis. The concentration of emitted X-rays from the magnetic poles appears to a distant observer as a periodic pulse of radiation as the beam sweeps past the observer, much like the rotating beam of a lighthouse. Wilson-Hodge's second pulsar discovery came on Sept. 7, 1998. At the same time, astronomers operating the RXTE's All-Sky Monitor noticed the same burst pattern in their data. The burst pattern makes it the 33rd member of a small, growing clan of transient, accretion-powered pulsars.
Accretion means that they are gobbling up material thrown off by a companion.
Transient means they turn on and off without warning. Unusual X-ray star bursts, pulses, puzzles. Things that go bump in the night . Jan. 21, 1998. Team finds that pulsars get wound up - and down.