A pulsar sends us regular pulses as its spinning neutron star sweeps a beam past Earth. Sometimes the pulses suddenly arrive closer together: the star has sped up. What triggers these large jumps when the star is usually slowing down?[1]
A neutron star normally spins down, but a large glitch makes its observed rotation suddenly faster. What releases an internal reservoir of angular momentum, and how does that release spread? In the superfluid framework, rotation is carried by vortices that can be pinned to the crust. As the crust slows, pinned regions can retain faster rotation; releasing vortices allows angular momentum to reach the crust. A chain of releases is a candidate trigger, rather than an observed interior event.[1][2]
Scope
The trigger and rapid dynamics of large spin-up glitches in rotation-powered pulsars.
What remains open
The trigger that releases this motion, and the speed of its release, are still debated.[1][2]
Inhomogeneous pinning models can produce particular rise and size distributions. Their assumptions and predictions still need discriminating tests; this scope does not require one mechanism for anti-glitches or every glitch class.[1][2]
Why it matters
The pulses let us watch an interior we cannot see directly. A jump and its recovery reveal how a hidden reservoir of rotational motion exchanges that motion with the star’s outer layers.[1]
The rise, size and recovery connect microscopic pinning to the rotation of an entire star. Comparing them tests how quantum fluid and solid crust exchange angular momentum under densities unavailable in ordinary laboratory matter; it also prevents a successful fit from being mistaken for a unique interior mechanism.[1][2]
Definitions
3 terms
pulsar
A rotating neutron star whose beam crosses our line of sight, producing the pulses recorded by a telescope.[1]
superfluid
A quantum state of matter that can flow without ordinary viscosity. In the glitch framework, part of the neutron-star interior stores rotational motion in this state.[1]
vortices
Lines around which superfluid circulation is concentrated in quantized amounts. Their motion and pinning help determine how a rotating superfluid exchanges angular momentum.[1][2]
A rotating neutron star whose beam crosses our line of sight, producing the pulses recorded by a telescope.[1]
superfluid
A quantum state of matter that can flow without ordinary viscosity. In the glitch framework, part of the neutron-star interior stores rotational motion in this state.[1]
vortices
Lines around which superfluid circulation is concentrated in quantized amounts. Their motion and pinning help determine how a rotating superfluid exchanges angular momentum.[1][2]