Re: VLP meeting logistics

[Parviz Ghavamian <parviz@pha.jhu.edu>]

Hi Una and Martin,

You mentioned electron-ion equilibration as one of the topics.  Given
the lack of Balmer-dominated shocks in Cas A, I was wondering whether
the first light Chandra image of Cas A was to be used as a baseline
for a proper motion study of the outer blast wave found by Eric
(Gotthelf et al. 2001 ApJ 552, L39).  A tight constraint on the
forward shock speed would be needed if we were to model the Cas
A VLP X-ray spectra of the thermally emitting parts of the
blast wave.  (I'm sure you already have thought of this)

So far, the Balmer-dominated shock spectra have only probed T_e/T_i
up to around 3000 km/s (SN 1006), so adding a data point at 5000-6000
km/s would be important.  If there is a significant amount of shock energy
lost to cosmic ray acceleration here as in E0102 (Hughes et al. 2000) then
the 1 megasecond of data on Cas A would be great for finally building
a more well-constrained model.

A discussion on this topic is warranted.  I could try putting together a
quick overview on T_e/T_i, though Jack and/or Steve would be better for
describing how CR acceleration would play into the modeling.

cheers,

-Parviz


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