VOEvent and RTML

[Roy Williams]

It is very encouraging to see interest being generated in VOEvent. I am sure we can 
make excellent progress in the first months of the year.

It is clear that the RTML people have built an excellent product that has 
considerable overlap with VOEvent. As Rick Hessman points out, what we are really 
doing is aggregating previously built schema with good namespacing -- thus in some 
cases, VOEvent will be simply an envelope for the RTML schema. If RTML can describe 
the status of the LIGO gravitational wave detector and the LSST telescope, then we 
will use it. From an IVOA perspective, we would like to interoperate the curation 
(publisher) and sky region specifications that already exist. We would like to make a 
uniform story on identifiers for the VOEvent packets themselves, as well as for 
publishing organization (see ref 1)

RTML uses the building blocks Contact, Target, Measurement, Instrument, Scheduling. I 
would suggest that the first four are relevant for VOEvent with this translation:

Contact = Who,
Target = Where and When,
Measurement = What
Instrument = How.

The first two are covered by both IVOA (see ref 2) and RTML schema.

On the question of "what" happened in the sky, we have two basic approaches. One is 
astrophysical ("a supernova happened"), and the other is a measurement ("the R 
magnitude increased by 3"). I would suggest a standard vocabulary for the 
astrophysical interpretation (see for example the Unified Content Descriptors -- see 
ref 3), and instrument-specific schema for the latter.

Roy Williams
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(1) IVOA Identifiers
http://www.ivoa.net/Documents/latest/IDs.html

(2) Resource Metadata for the Virtual Observatory
http://www.ivoa.net/Documents/latest/RM.html

(3) Unified Content Descriptors
http://ivoa.net/Documents/PR/UCD/UCD-20041026.html
http://www.ivoa.net/internal/IVOA/IvoaUCD/WD-UCDlist-20040823.pdf

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California Institute of Technology
roy at caltech.edu
626 395 3670