Cas A VLP planning meeting

[Una Hwang <hwang@orfeo.gsfc.nasa.gov>]

Dear All,

The Cas A SNR will be observed by Chandra this spring for a
total of 1 Million secs (a Chandra "Very Large Project").
This will be by quite a long way the richest dataset on a
supernova remnant yet, and will probably remain so
unless/until Chandra executes another SNR VLP. In
particular, the statistical quality of the data will be such
that one can think about exploiting the spatial resolution
of the Chandra telescope to the fullest extent. No future
X-ray mission is planned to have such capability.

Following a meeting at Rutgers University in December 2002
to discuss possible Chandra SNR VLPs, the outcome of which
was this proposal, we now invite all potentially interested
people to a meeting to be held at Naval Research Lab in
Washington DC, May 6/7 2004 to discuss data analysis
strategies and assumptions, and coordinate different aspects
of the work among the interested parties.  We hope to
initiate some e-mail discussion in the two months before.
You are receiving this email as a potentially interested
party to these discussions.  (We apologize for the nonsense
test message inadvertantly sent out yesterday!)

(If you are NOT interested in receiving further emails then
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or contact one of us at the email addresses below.)

If you ARE interested, please read on:

We would appreciate an initial response to whether you are
likely to attend the meeting (to get an early idea of
numbers; those of you who have already responded can
disregard this point). Please reply with these details to

   hwang@orfeo.gsfc.nasa.gov 
          and
   jlaming@ssd5.nrl.navy.mil.


Details of logistics (hotels, how to get to NRL, etc) and a
tentative meeting agenda will follow. The conference room is
booked for 8.00 am - 5.00 pm both days. If anyone is
thinking coming to Washington on the morning of May 6th
rather than the day before we can start around 10.00 am on
May 6th to facilitate this. US citizens and permanent
residents do not need to be escorted while on the NRL
campus, though you do need to get a visitor's badge upon
arrival. All other foreign nationals will need to be
escorted by an NRL employee, i.e. Martin Laming, so if you
fall into this category, let us know when responding to this
message, together with your nationality and institutional
affiliation.

The proposal text is available for download at
   http://lheawww.gsfc.nasa.gov/users/hwang/casavlp.html
The two papers central to it (Laming & Hwang 2003, Hwang &
Laming 2003) are now published in ApJ (vol 597, pages 347
and 362) and are also available at the same website.

It is our intention to devote the first day of the meeting
to discussions regarding the specific proposal goals,
element abundances as a function of ejecta mass coordinate
from x-ray knot spectra and determinations of the explosion
asymmetry, with particular emphasis on the Fe ejecta. Other
topics relevant to this (which we mention here for some
ideas to start with) are:

* Proper motions of forward shock and ejecta knots, can we
determine an explosion center and hence a pulsar kick like
Thorstensen, Fesen and others did in the optical?

* Electron-ion equilibration at shocks. Studies of the
forward shock should be straightforward, but can we identify
the reverse shock location and try something similar there?

* Fitting of jet and anti-jet knots. Should be
straightforward but interpreting them in the same way as the
other knots will need improved hydrodynamic models.

* Can we find Sc and Ca K alpha emission in faint regions?
These follow from the electron capture decays of 44Ti and
44Sc, and with the observed flux in 44Sc and 44Ca gamma
rays, there should be around 2000 of these photons in each
line in the 1 Ms Chandra observation. Background
subtraction/reduction will be the key.

On the second day we would hope to discuss some other
things, x-ray sychrotron emission from the forward shock and
elsewhere, electron acceleration processes at the contact
discontinuity, further usual comparisons with optical HST
data, point source spectrum, and anything else that
arises...

We ask that when you post email to the group you use the 
address
   casa_vlp@athena.gsfc.nasa.gov 
and that you use a NEW SUBJECT when starting a new topic and
keep the SAME SUBJECT when replying to a previous message on
a particular topic.  This will help us keep the email 
archive in order.

Thank you!

Una Hwang
Martin Laming