SSAP clients for theoretical spectra

Miguel Cerviño mcs at iaa.es
Mon Oct 15 00:58:47 PDT 2007


Dear Doug,

> The key thing here is what is the data which is returned.

 From this point of view, considering what is returned *at the very  
end*, I completely agree with you, but the point raised by Carlos,  
Ulrike and myself is not only about the very final data returned, but  
about how to ask the data!
Currently, it is not possible to access theoretical spectra excepting  
by VOSpec, but
some applications are implementing "ad hoc" the theoretical spectra  
inside them because
they need it for analysis (e.j. specview).

I think that the key point is that there are theoretical spectra  
services, but most  apps (all expecting VOSpec) that provide SSAP  
access does not access it.  So, there is a very high risk to lost  
these brach of theoretical astronomy in the VO, and, hence, the  
development of proper analysis tools (i.e. to be able to evaluate if  
the scientific result is a model independent robust result).

I still think that if this services can be registered not only as  
SSAP but WITH another "keyword" that allows apps to know that the  
query is a "format=metadata" can solve part of the problem.
Or, in other words, thinking about what is returned:

- a "standard" SSAP query returns an spectra
- a "format=metadata" SSAP query returns a set of metadata that the  
user must select and,
     *after that*, the service returns an spectra

So even at this level, what is returned *first* by the service is  
different, although the very final result (an spectra obtained in 1  
or 2 steps) is the same.

> If you are returning more general theory data ....
> ... this might also be getting into the realm of what has been called
> SNAP, for real theory data.

About SNAP, it is not the case. SNAP is designed to access (and  
explore) theoretical
databases that can be parametrised in N independent physical axes  
(e.j. N-body simulations)
But it is not valid for other theoretical data like isochrones,  
tracks, star formation histories of galaxies etc...

cheers

	Miguel




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