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.
Astronomers discover bursting pulsar .
May 23, 1996. Return of the bursting pulsar - June 1996. Pulsar goes off twice each orbit. The Astrophysical Journal on-line. We think the rest are similar.