VOEvent query language (SEAP?)

[Rob Seaman]

Elizabeth Auden wrote:

> 1. Astronomer has a favourite event (say, a microlensing event  
> published in the OGLE feed) or just really likes microlensing  
> events. The astronomer wants to find all observations of the same  
> part of the sky where the event took place

> 2. The astronomer may have a set of observations - say, 2MASS data  
> - and he or she wonders if these observations happened to catch any  
> interesting events. A similar set of use cases applies - the  
> astronomer may want the same spatial location in the sky, but a  
> different spectral or temporal view.

Ok.  Interesting.  In general, I have an event, give me data - or - I  
have data, give me events.

One thing I think we need is for our query discussions to occur in  
the larger context of real-time event delivery.  Datascope handles  
the event->data use case, but surely as we move into the era of tens  
of thousands of events daily this strategy of repeatedly querying the  
entire federated VO holdings for each event is going to fail to scale.

A third use case, as other's have said, is to correlate several live  
event streams against each other.  After all, many of the science  
cases require "fresh" events for any chance of success.  We've called  
a broker that correlates multiple streams an aggregator, but what  
does this mean about its architectural design?  (And isn't correlator  
a better term?)

Rob