Modeling the Surface Emission and Viewing Geometry of PSR J0821-4300 in Puppis A
Abstract
We summarize our latest results on applying the antipodal emission model to the central compact object (CCO) in the supernova remnant Puppis A. This model assumes two opposing thermal hot spots on the surface of the neutron star (NS) and includes a spectral feature located to the cooler pole, whose flux may be variable in time. The antipodal is able to reproduce the unique observational properties of the pulsar, its overall spectral shape, energy-dependent pulsed modulation, and the abrupt 180 degree phase reversal at the crossover energy of the two fitted blackbody components. Using the latest phase-connected timing solution for PSR J0821-4300, based on 200 ks of XMM and Chandra observations spanning 2 years, we compare the energy dependent profile with the model predictions in sufficient detail to further constrain the antipodal model. We consider any time evolution of the spectrum, in particular, the spectral deviations from a pure blackbody evident on the cooler pole. We also present our latest measurement of the period derivative, accurate to 5%, that has likely reached the Shkloski limit for the high proper motion NS, whose spin-down rate is nearly imperceptible. With a timing estimate of the magnetic field of order 10^11 Gauss, the essential problem in understanding PSR J0821-4300 and the other CCO pulsars is how to reconcile their highly anisotropic emission without creating a strong external dipole magnetic field.
- Publication:
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American Astronomical Society Meeting Abstracts #220
- Pub Date:
- May 2012
- Bibcode:
- 2012AAS...22031903G