ANGULAR MOMENTUM TRANSFER IN VELA-LIKE PULSAR GLITCHES

Journal Article · Sat Dec 10 04:00:00 EST 2011 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/743/1/L20· OSTI ID:22047305

The angular momentum transfer associated with Vela-like glitches has never been calculated directly within a realistic scenario for the storage and release of superfluid vorticity; therefore, the explanation of giant glitches in terms of vortices has not yet been tested against observations. We present the first physically reasonable model, both at the microscopic and macroscopic level (spherical geometry, n = 1 polytropic density profile, density-dependent pinning forces compatible with vortex rigidity), to determine where in the star the vorticity is pinned, how much of it is pinned, and for how long. For standard neutron star parameters (M = 1.4 M{sub Sun }, R{sub s} = 10 km, {Omega}-dot = {Omega}-dot{sub Vela} = -10{sup -10} Hz s{sup -1}), we find that maximum pinning forces of order f{sub m} Almost-Equal-To 10{sup 15} dyn cm{sup -1} can accumulate {Delta}L{sub gl} Almost-Equal-To 10{sup 40} erg s of superfluid angular momentum, and release it to the crust at intervals {Delta}t{sub gl} Almost-Equal-To 3 years. This estimate of {Delta}L{sub gl} is one order of magnitude smaller than that implied indirectly by current models for post-glitch recovery, where the core and inner-crust vortices are taken as physically disconnected; yet, it successfully yields the magnitudes observed in recent Vela glitches for both jump parameters, {Delta}{Omega}{sub gl} and {Delta}{Omega}-dot{sub gl}, provided one assumes that only a small fraction (<10%) of the total star vorticity is coupled to the crust on the short timescale of a glitch. This is reasonable in our approach, where no layer of normal matter exists between the core and the inner-crust, as indicated by existing microscopic calculation. The new scenario presented here is nonetheless compatible with current post-glitch models.

• OSTI ID: 22047305
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 743; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANGULAR MOMENTUM
ANGULAR MOMENTUM TRANSFER
ASTROPHYSICS
LAYERS
MAGNETIC FLUX
NEUTRON STARS
PULSARS
SPHERICAL CONFIGURATION
STAR MODELS
SUPERFLUIDITY
VORTICES