Theoretical spectra for the Cas A VLP

[Carles Badenes <badenes@ieec.fcr.es>]

	Hello everybody,

	Among the projects outlined by Una and Martin, I am mostly
interested in the one about 'Refining models to produce theoretical
spectra for direct comparison with data'.

	In fact, this is already done, even though the level of accuracy
could be much improved. With a lot of help from Kazik Borkowski, I have
been using the Hamilton & Sarazin spectral code (aka neivers 1.1. in
XSPEC) to produce synthetic spectra from my own hydrodynamics + NEI
ionization calculations. Here's a few things I would like to discuss with
whoever is interested:

	- Atomic data. Right now, the synthetic model spectra for NEI
plasmas are limited by the quality of the atomic data. Can we do something
about this? If not, what are the pitfalls to avoid?

	- Analysis techniques. Once model spectra are produced, what is
the best way to compare them with the data? In the case of knots,
relatively simple spectral analysis is reasonable, but what of regions
where the single ionization timescale hypothesis does not apply?

	I would also like to point out another topic for discussion:
core-collapse SN explosion models. One of the main goals of the VLP
proposal is to establish links between the Cas A SNR and the
nucleosynthesis that took place when the supernova exploded. But
core-collapse SN are diverse, and models are probably even more diverse.
Expertise in core-collapse SN models would be crucial to fully explore
issues like jet formation and ejecta overturn.

	See you in a few weeks,

			Carles Badenes

Carles Badenes Montoliu +++++++++++++++++++++++++++++++++++++++++++
INSTITUT D'ESTUDIS ESPACIALS DE CATALUNYA (IEEC)  and  UNIVERSITAT
POLITÈCNICA DE CATALUNYA (UPC)
Edifici Nexus-201, Gran Capita 2-4, Barcelona 08034, SPAIN
Phone: +34 93 205 85 24    Fax: +34 93 280 63 95
E-Mail: badenes@ieec.fcr.es