GRAVITATIONAL WAVES FROM NS INTERIORS

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GRAVITATIONAL WAVESFROM NS INTERIORS

• C. Peralta, M. Bennett, M. Giacobello, A.
  Melatos, A. Ooi, A. van Eysden, S. Wyithe (U.
  Melbourne and AEI)
• Superfluid turbulence
• Post-glitch relaxation
• Rigorous model ? parametrised template ? nuclear
  physics (viscosity, compressibility)

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CONTINUOUS SOURCE
C-C diff. rotation (glitches)? nonaxisymmetric
superfluid flows

• Long-lived (days ? years) periodic signal
• Superfluid turbulence as pulsar spins down (Re
  1011)
• Post-glitch relaxation (Ekman pumping)
• Follows burst signal of glitch itself (msec?)
• Not discussed here...
• R-modes continuously excited in core (Andersson
  et al. 99 Nayyar Owen 06) cf. ocean r-modes
  (Heyl 04)
• Amplitude and threshold probe superfluid core and
  viscous crust-core boundary layer (Lindblom
  Mendell 99 Bildsten Ushomirsky 00 Levin
  Ushomirsky 01)

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SUPERFLUID CIRCULATION
oscillating hydro torque
EKMAN PUMPING
Re104
(Peralta et al. 05, 06, 07)

• Differential rotation ? meridional circulation
• superfluid ? HVBK two-fluid model (3D)
• Quantised vortices ? mutual friction

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MACRO SF TURBULENCE
TAYLOR VORTEX
HERRINGBONE SPIRAL
TURBULENCE
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(No Transcript)
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POST-GLITCH RELAXATION

• Ekman fluid spun up in radially expanding
  boundary layer (meridional ? Coriolis)
• TEkman (2E1/2W)-1 with E n(2WR2)-1 Re-1
• Buoyancy inhibits meridional flow less/more
  according to compressibility K
• Brunt-Vaisala frequency N2g2(ceq-2-K-2)
• Incompressible K ? 8. Unstratified N ? 0
• Nonaxisymmetric perturbation ? exp(imf)
• Wave strain

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GW SPECTRUM

• Lorentzian measure width peak frequency
• Extract two of E, N, K if W known (X-rays)
• Width ratio independent of E (i.e. viscosity)
• Amplitude depends on distance, orientation, DW,
  and compressibilities but not E
• Poln ratio orientation to line of sight (also
  N, K)

EQUATORIAL OBSERVER
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K 0.1
N 1
K 0.3
h(f)
K 1
K 3
f
N 0.1
K 1
h(f)
N 0.3
N 3
f
N 1
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EXTRACTING NUCLEAR PHYSICS
E
K
N
i
i
i
E
E
K
N
K
N
Total signal including current quadrupole
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PHYSICS TO WORRY ABOUT

• Microscopic turbulence
• DGI ? tangle of quantized vortices
• Affects the mutual friction coupling ?
• Macroscopic turbulence (Kolmogorov eddies)
• Do large or small eddies dominate the GW signal?

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WHAT WILL LIGO TEACH US?

• SF turbulence
• Is the core superfluid?
• Mutual friction entrainment parameter
• Viscosity
• Crust-core coupling

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• Glitches
• Measure ceq and K for nuclear matter
• Do glitches happen faster or slower than one
  rotation period?
• Probe seismic (avalanche) dynamics
• Spectrum of non-axisymmetric excitation
• NO OTHER GOOD WAY
• TO LEARN SUCH THINGS!