RAPID RECOVERY OF THE VELA PULSAR FROM A GIANT GLITCH

OBSERVATIONS of the rotational behaviour of pulsars have shed much light on the structure of neutron stars. In particular, the response of the Vela pulsar (PSR0833-45) following each of seven giant glitches (sudden increases in rotation rate v of magnitude δv/v≈10-6, and in the derivative, δv̇/ v̇≈10-2) has been a recovery on two timescales, of about 6 and 60 days. This has been interpreted as evidence for the existence of distinct regions of neutron superfluid within the stellar crust2. Here I report observations that started 35 minutes after the eighth glitch of PSR0833-45, which reveal a hitherto unseen glitch component: a (12 ±1)% increase in the slowdown rate v̇ (the largest so far seen), most of which decayed away over 0.4 days. These data support the existence of at least two superfluid components in the stellar crust that are coupled linearly to the normal crust, as suggested recently by Alpar et al..3. © 1990 Nature Publishing Group.