Introduction
The objective of the VOEvent effort is to define the content and meaning of a standard information packet for representing, transmitting, archiving, and publishing a discovery of an immediate event in the sky. Version 1.11 of the VOEvent standard has been adopted as a recommendation by the International Virtual Observatory Alliance. The job of developing a contiguous astronomical transient alert network has centered around the emerging VOEventNet infrastructure.
NOAO is active in all these efforts. The National Observatory's interest derives from a vision of pursuing time domain astronomy as a key area of research and infrastructure building. Several of the NOAO Survey projects include a time domain component, the time domain forms a significant part of many of the projects called out by the latest decadal survey, and many among our large user community are dependent on the time domain, in particular on the detection, announcement and follow-up of transient astronomical events. NOAO is prototyping its VOEvent infrastructure using supernova alerts generated by the ESSENCE project.
