1. After the Supernova: Pulsars Melissa Anholm University of Wisconsin-Milwaukee 29 September, 2008

2. OutlineOutline Properties of Neutron Stars Large Magnetic Field Rapid Rotation Origin of the Pulsing Effect Motion in a Magnetic Field Light Emission The Lighthouse Effect

3. A Typical Neutron Star Strong Magnetic Field Strong Magnetic Field Fast Rotation Fast Rotation Properties of Neutron Stars

4. Why does it spin so fast? A typical young pulsar completes about one rotation per second. Properties of Neutron Stars A typical star completes about one rotation every week - month.

5. Magnetic Fields - Now with Lines! http://www.freewebs.com/ayxl/magnet.jpeghttp://www.utm.edu/staff/cerkal/magnetic_files/image004.jpg Properties of Neutron Stars

6. After the Collapse: Rotation and the Magnetic Field Dense magnetic field lines  Strong magnetic field Angular momentum conserved  Fast rotation Magnetic and rotational axes may not be aligned. Properties of Neutron Stars

7. Misalignment of Magnetic and Rotational Axes - Why We Care http://www.atnf.csiro.au/news/press/images/binary_pulsar/ All newly formed neutron stars (and some older ones, too!) produce beams of light along their magnetic poles if the axes aren’t aligned. Origin of the Pulsing Effect

8. Properties of Light Origin of the Pulsing Effect “photon” = a particle of light accelerating charged particles produce photons (!)

9. Moving magnets produce an electric force. Electric currents and moving charged particles produce a magnetic force. A Strange Connection between Electricity and Magnetism http://img105.imageshack.us/img105/5114/magfield0ct.jpg Origin of the Pulsing Effect Result: a moving charged particle in a magnetic field will accelerate.

10. Motion on a Large Scale Near a Rotating Magnet http://www.atnf.csiro.au/news/press/images/binary_pulsar/ Charged particles move upward or downward (depending on the charge) at the pulsar’s rotational poles. Origin of the Pulsing Effect

11. Motion in a Magnetic Field A charged particle placed in a magnetic field will spiral around the magnetic field lines. Origin of the Pulsing Effect

12. Accelerating A Charged Particle Synchrotron Radiation = Light Light is emitted in a direction perpendicular to the magnetic field. Origin of the Pulsing Effect

13. The Lighthouse Effect Origin of the Pulsing Effect

14. Conclusions Pulsars are rapidly rotating neutron stars with powerful magnetic fields. A misalignment in the rotational and magnetic axes leads to the emission of beams of light from a pulsar’s magnetic poles. http://www.shatters.net/forum/viewtopic.php?t=11372