Light curves in DAL

Roy Williams roy at caltech.edu
Tue Sep 25 08:24:34 PDT 2012


I would like to point out that VOEvents have always been intended to 
carry light-curve information; both the Gaia and LSST missions are 
expecting to put light curves in their events. After a long discussion 
in 2007-9, and an expectation of IVOA reaching a decision on a light 
curve representation, we built the standard around the "utype" consensus 
that was emerging.

Therefore section 3.3.3 of the VOEvent specification (*) defines the 
<Table> element, based on a simplification of VOTable, where ucd and 
utype carry the semantic information. The intention was to put the light 
curves in such a Table structure.

I would be very disappointed to have SimpleTimeSeries come back, with 
its IVOA-incompatible time standards, its assumption that all time 
series are optical light curves, the assumption that all time series are 
measured in magnitudes, and its complicated non-tabular representation 
where magnitude error is first class quantity.

Please can the IVOA just use a table with semantics via utypes, as we 
were promised years ago?

Roy Williams

(*) http://www.ivoa.net/Documents/VOEvent/20110711/REC-VOEvent-2.0.pdf

---
Caltech LIGO
roy at caltech.edu
626 395 3670


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