1. Mass and Radius Constraints Using Magnetar Giant Flare Oscillations Alex T. Deibel With: Edward F. Brown (Michigan State University) Andrew W. Steiner (INT, University of Washington) HEAD Meeting 2013Apr-8-2013

2. Giant flares triggered by crust reconfiguration Modeled crust oscillations can be compared to QPOs Strohmayer & Watts 2006 Figure: Robert Duncan Deibel Apr-8-2013 Magnetar Giant Flares - QPOs

3. Deibel, Steiner, and Brown 2013 (submitted) Deibel Apr-8-2013 Nuclei crystal lattice Neutron-rich nuclei Degenerate electron and neutron gases Magnetic field melts the crust and changes crust thickness Crust composition

4. Deibel Apr-8-2013 BzBz BzBz Surface Core Neutron Drip Outer Crust (Z, N), e Inner Crust (Z, N), e, n    ’ = 0 Perturbing the crust

5. Equilibrium Nuclei Deibel Apr-8-2013 Solve for  = Schumaker & Thorne 1983 Piro 2005 Samuelsson & Andersson 2007 Steiner & Watts 2009 Assigning crust modes to QPO frequencies

6. Constraining masses and radii Deibel Apr-8-2013 EOS: Steiner et al. 2010 Deibel, Steiner, and Brown 2013 (submitted)

7. Summary Choose a mass and radius from Steiner et al. EOS Integrate perturbation through the crust Compare eigenmodes to QPOs Magnetar masses and radii agree to within 1  with PREs and LMXBs from Steiner et al. 2010 Deibel Apr-8-2013 Find crust composition and shear modulus

8. Extras

9. Discovery of Magnetars Class of pulsars with recurring gamma ray emission (SGRs) Getting the magnetic field: Observe a pulsar’s period and spin-down rate Assume a moment of inertia to get a dipole magnetic field Deibel Apr-8-2013

10. 10 km 1 km Core Crust superfluid atmosphere Deibel Apr-8-2013 QPOs are torsional modes Oscillations confined to the crust Crust modes will depend on crust composition Crust Modes

11. Shell effects Deibel Apr-8-2013 Magnetic Field - Landau Quantization - Magic Numbers Dieperink 2009

12. With shell effectsNo shell effects Deibel Apr-8-2013 Model addition (1): Shell Effects

13. B = 0.0 GB = 2.0·10 15 G Deibel Apr-8-2013 Model addition (2): Magnetic Field

14. Core equation of state Deibel Apr-8-2013Steiner, Lattimer, Brown 2010 1.5 M  1.0 M 