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Meissner Effect in Strange Quark Stars
AXPs/SGRs (Anomolous X-Ray Pulsars/Soft-Gamma Repeaters) in the context of Strange Quark Stars
  • Paper I - (accepted to ApJ) 3D Numerical simulations (MHD) of the magnetic field alignment and emission.
  • Paper II - (ApJ Letters) Spin down through vortex expulsion from AXPs/SGRs into Radio Quiet Isolated Neutron Stars (RQINSs)
  • Paper III - (submitted to ApJ) Fall-back crust around a quark-nova compact remnant I: The degenerate shell case with applications to SGRs, AXPs and XDINs
  • Paper IV - (submitted to ApJ) Fall-back crust around a quark-nova compact remnant II:
  • My Thesis - (M.Sc. Thesis) A New Model for Soft-Gamma Ray Repeaters and Anomalous X-ray Pulsars using Quark Stars

Relation between quiescent phase X-ray luminosity and spin-down rate
Lx vs. Pdot Plot of the relation between quiescent phase X-ray luminosity and spin-down rate. By using magnetic vortex expulsion due to spin-down from magnetic braking, two observables (Lx and Pdot) can be used to fit SGRs, AXPs and XDINs.

Animations of Magnetic Field Re-Organization (WARNING: Large MPEG Files)
3D TIME=300s (spatial rotation)   Animations of the magnetic field around a quark star following the onset of superconductivity in the stars interior. Upon the transition to a quark star, the Meissner effect causes the interior magnetic field to be constrained to vortices that are aligned with the star's rotation axis.

  The exterior field, which was a misaligned dipole before superconductivity, is now forced to align itself with the rotationaly-aligned interior field.

  Rotation axis is along the z direction. Field lines are represented by the magnetic vector potential in the direction orthogonal to the viewing plane.
XZ Plane (time evolution)
XY Plane (time evolution)

Beta*Intensity versus Time
Beta=1, Theta=15,30,60   Total (normalized) intensity emitted (beta02 * Is) versus time for beta=0.3 and theta=15, 30, 60 degrees (angle between rotation and initial magnetic dipole axis).

  We note that the higher the inclination angle, the longer it takes for the outer magnetic field to align itself. This can be seen in the figures where the tail takes longer to flatten for higher angles. Furthermore, the high inclination run shows oscillations which can be linked to stronger reconnection events.

 
Theta=15, Beta=0.1,1,10

Normalized Magnetic Energy (B^2) Released over Time
Theta=30, Beta=.1,1,10   Magnetic energy lost over time. The change in magnetic energy can be estimated from these plots to be between 0.4-0.6, implying that energies of order 1044 erg are released during the event.



Brian Niebergal - bnieber at phas dot ucalgary dot ca