1. Calculating the moment of inertia of neutron stars Jacobus Diener Stellenbosch University, RSA Dr Alan Dzhioev and Prof Victor Voronov Bogoliubov Laboratory of Theoretical Physics, JINR

2. Pulsar: Quantity of interest Pulsars  Rapidly rotating remnant star of massive star that exploded in core-collapse supernova  Radius ~10 km  Mass ~1.4 M  (solar mass)  Density ~10 15 g/cm 3 (few times nuclear density)  Radio-emission from magnetic poles  Sudden spin-ups in frequency (glitches) Pulsars modelled as giant nuclei  Constraining models proven difficult with observational data

3. Models and constraints Models for nuclear matter Equation of state Mass-radius relationship for different models of nuclear matter. Observational constraints given by mass-radius relationship of EXO 0748-676 (purple) and General Relativity (black).

4. Glitch models Alpar et al. model glitch as two components differential rotating in the pulsar. Outer crust spin downs faster than superfluid interior due to magnetic torques Angular momentum transferred between two components resulting in spin-up of star. Size of spin-up related to moment of inertia of different layers

5. Calculating moment of inertia Rapidly rotating ultra-dense fluid Framework proved by General Relativity General expression for moment of inertia Relativistic effects  Rotation  Breaking of spherical symmetry  Frame dragging

6. South African context Hartebeesthoek Radio Astronomy Observatory  26 m radio-telescope  Vela glitch data spanning 20 years SA SKA/MeerKAT 26 m telescope at HartRAO

7. Furthermore… Presented a talk to students at the BLTP on the main aspects of my studies so far Discussed possible nuclear matter calculations with Dr V. V. Burov using the Bethe-Salpeter approach

8. Conclusion Expression for moment of inertia derived To be able to solve more study of rotating, axial symmetric relativistic fluid further study needs to be undertaken Could provide publishable results when compared with long-term glitch data of the Vela pulsar from HartRAO

9. For organising and financing this visit thanks to the National Research Foundation (South Africa) and the Joint Institute for Nuclear Research. Acknowledgements References M.A. Alpar, H.F. Chau, K.S. Cheng & D. Pines, ApJ, 409, 345 (1993). J.M. Lattimer & B.M. Schutz, ApJ, 629, 979 (2005). B. Link, R.I. Epstein & J.M. Lattimer, Phys. Rev. Lett., 83, 3362 (1999). F. Weber, Prog. Pat. Nucl. Phys. 54, 193 (2005).