Specview with VO interface released

[Ivo Busko]

Hello, Philippe

Overploting models is something that can be done right 
now in specview. See this page:

http://specview.stsci.edu/javahelp/Templates.html

Basically a model is a spectrum like any other, in
which the units for the flux axis are *not* part of
the current specview units library. This is a temporary 
solution though, one must base the decision, I guess,
on the flux UCD or something in those lines.

However, doing quantitative comparisons, as required by a 
fitting algorithm, is another matter. There are three 
parts to this problem:

1 - we should be able to access model data and make it 
available to the specview fitting code in an efficient way.
It doesn't matter if we use a SSAP-type access, or a web
services type of access, in both cases we should be able
to access the data with queries that are based on the model
physical parameters. A caching mechanism should probably
be necessary as well in order to prevent duplicate retrievals
from the remote site. 

2 - one must add a "spectral component" to the existing 
library of spectral components in specview. This can be
done right now by the specview user (if anyone is willing to
try :-) ). It will be implemented later on in the specview 
component library distributed with the software, whenever we
can solve issue (1) above.

3 - the actual data being fitted should provide "resolution"
or "bandpass" information for each data point, so the proper
resampling and chi-squared computations can be performed. This
is addressed by the Resolution and/or Accuracy elements of
the SED data model, but implementation is still on the air.
Can we populate those elements on an ad-hoc basis, using, say,
the distance in wavelength between successive data points in
a spectrum as a measure of the bandpass of each data point? 

-Ivo


Philippe Prugniel wrote:
> 
> Hello,
> 
> This is great to have this VO-SSA access in specview...
> 
> Specview has nice fitting features, and I am sure everybody would like
> to extend them (for example to implement SED fitting as was shown
> during the AVO science demo last January). I understand that for
> mass processing it will be better done on server side, as the astrogrid
> workflow
> intend to do. But still having fitting capabilities in the client is really
> nice for small interactive tasks.
> 
> As a first step I would like to overplot a model, and as a model provider
> I would like to understand what is required to have them plugged in
> specview (or other clients).
> 
> We had last week a meeting in France (VO-France) where we
> discussed of several models producing or analysing spectra. For example,
> Igor Chilingarian advertized in the TVO-IG forum one of these models,
> Pegase.HR http://vo.obspm.fr/cgi-bin/siap/pegasehr.pl
> This service is build as a fake SSA in the sense that the input parameters
> are not those of SSA (there is no position on the sky for a model), but the
> answer is that of a SSA (VOTable with reference to a FITS binary table).
> 
> Could such a service be accessed as it is from specview (with a special
> formular
> to pass the physical parameters)? Or shall we move right now to web
> services?
> 
> Sincerely. Philippe Prugniel.