Monday, August 13, 2007

Discussion: Monday Morning Session

These are some comments, paraphrased from the speaker, during the 20-minute discussion following the morning session. For the complete -- and correct -- version of this discussion, I recommend going to the webcast page and watching it yourself. You can add your own comments and amplications as attached coment.

Vicky Kaspi: What sorts of observations would be most useful for testing your models?

A. Spitkovsky: The kinds of observations we heard about this morning (drifting subpulses) are certainly useful. GLAST will tell us something.

Y. Lyubarsky: Agree with Anatoly.

J. Weisberg: Observers should keep an open mind about their work, as the appearance / disappearance of pulsars turns out to be a very interesting phenomenon...

Jon Arons: It's clear these objects produce a pair-plasma, and that must also produce gamma -rays. For GLAST, with 30x improved sensitivities, if it does not detect gamma-ray emission, there will need to be a lot of erudite theorist squirming to explain that. Also, what is the carousel? The basis of the magnetospheric model which now exists can be used to produce a modulating wave model through that magnetosphere -- explorations in this direction may be quite useful.

Peter: Since it seems that the torque on the magnetic field axis towards alignment or towards orthogonality must act on a short timescale, then why are not most pulsars either aligned or orthogonal and is this explained in your models?

A. Spitkovsky: I have not looked at the torques in my models at a quantitative level. However, if the torques were really large then almost every pulsar would be precessing and that is not seen.

J. Arons: Timescale of alignment depends on internal structure.

D. Lai: I think the theoretical situation is not promising. Example, Anatoly's simuations stil produce a braking index of three, and to get a different braking index, some other physics must be introduced. Perhaps you can comment on this.

A. Spitkovsky: Nature need not be "nice", and so this would lead to not a "nice" model. This requires introducing more complicated physics; it is an unclean problem, yes.

P. Weltevrede: Is there only one drifting sub-pulse?

J. Rankin: Perhaps not all the bright components in the center of pulses are not cores.

D. Lai: Following on J. Arons' comment. How would you differentiate between carousel drifting subpulses, and a wave-type configuration Jon refers too?

--- D. Fox, R. Rutledge

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