VOEvent

VOEvent is a standardized language used to report observations of astronomical events; it was officially adopted [cite press release
title = VOEvent becomes International Standard
publisher = US National Virtual Observatory
date = 2006-11-13
url = http://www.us-vo.org/news/story.cfm?ID=31
accessdate = 2007-08-25 ] in 2006 by the International Virtual Observatory Alliance (IVOA). Though most VOEvent messages currently issued are related to supernovae, gravitational microlensing, and gamma-ray bursts, they are intended to be general enough to describe all types of observations of astronomical events, including gravitational wave events. Messages are written in XML, providing a structured metadata description of both the observations and the inferences derived from those observations. The rapid dissemination of event data with a formalized language was the original impetus [cite conference | last = [http://astro.berkeley.edu/~jbloom Joshua S. Bloom]
coauthors = Wozniak, P.; Williams R.
date = 2004-09-17
year = 2004
month = 17
title = VOTransients: Adding the Temporal Domain
conference = NVO Summer School 2004
conferenceurl = http://www.us-vo.org/summer-school/2004/proceedings/index.cfm
location = Aspen, CO
booktitle =
url = http://lyra.berkeley.edu/~jbloom/rtvo/public_html/docs/rtvo_talk_html/siframes.html
accessdate = 2007-08-20 ] for the creation of VOEvents and the network (now called [http://voeventnet.org VOEventNet] ) used to transport the messages; indeed VOEvent messages are designed to be compact and quickly transmittable over the internet. The VOEvent language (which is codified in an XML schema) continues to evolve; the [http://ivoa.net/Documents/latest/VOEvent.html latest version is 1.11] .

History

VOEvent builds upon previous generic publishing schemes such as International Astronomical Union Central Bureau for Astronomical Telegrams (IAUCs and CBETs) and the [http://www.astronomerstelegram.org/ Astronomer's Telegrams] (ATELs). The principal difference is that VOEvent messages are intended to be automatically parsed and filtered whereas ATELs and IAUCs are intended to be read by humans. The scope of VOEvent is informed by several other messaging schemes used to facilitate rapid discovery announcements for specialized sub-fields of astronomy (such as OGLE microlensing alerts and Supernova Early Warning System). The closest ancestors of VOEvent are The Telescope Alert Operation Network System (TALON) [cite conference
last = White
first = R.
coauthors = Wren, James; Davis, Heath R.; Galassi, Mark; Starr, Daniel; Vestrand, W. T.; Wozniak, P.
title = TALON: the telescope alert operation network system: intelligent linking of distributed autonomous robotic telescopes
booktitle = Advanced Software, Control, and Communication Systems for Astronomy
editor-last = Lewis
editor-first = Hilton
editor2-last = Raffi
editor2-first = Gianni
pages =302-312
volume = 5496
doi = 10.1117/12.549438
date = September 2004
url = http://adsabs.harvard.edu/abs/2004SPIE.5496..302W
accessdate = 2007-08-25 ] and the Gamma Ray Burst Coordinates Network (GCN) messages, used extensively by the gamma-ray burst community.

Structure of the Language

A [http://ivoa.net/Documents/REC/VOE/VOEvent-20061101.html#examples typical VOEvent message] contains the following tags:

* - describing who is responsible (the author and the publisher) for the information contained in the message
* - a description of the instrumental setup on where the data were obtained
* - the data (such as source flux) associated with the observations of the event
* - inferences about the nature of the event
* - description of the time and place where the event was recorded. This draws from the [http://www.ivoa.net/Documents/latest/STC.html Space-time Coordinate] (STC) recommendation to the IVOA.

A well-formed VOEvent message must validate against the [http://www.ivoa.net/xml/VOEvent/VOEvent-v1.1.xsd VOEvent schema] (.xsd). A valid message may omit most of the informational tags listed above, but since the creation of VOEvent messages is done automatically, most opt to transmit the fullest content available.

Current Uses

As with most products of the Virtual Observatory, there are no promises that once a VOEvent message has been issued, it will persist indefinitely. It is the role of the publisher, generally, to maintain and curate VOEvents issued. Still, public VOEvent messages may be distributed and or archived through 3rd parties.

VOEvent Feeds

There are live VOEvent feeds (through a variety of protocols, such as RSS and Jabber) currently available from:
* The [http://voeventnet.caltech.edu/ Caltech] VOEvent group.
* [http://www.estar.org.uk/wiki/index.php/VOEvent eStar] (Exeter, England)

Vizualizations

Since VOEvents note the location and time events, it is possible to convert streams of events into temporal or spatial visualizations. eStar hosts an AJAX mashup of [http://vo.astro.ex.ac.uk/ogle/cgi-bin/timeline.cgi microlensing events] . The [http://voeventnet.org VOEventNet collaboration] has produced a kml-based stream of VOEvent visualizations for Google Sky.

References

External links

* [http://ivoa.net/Documents/latest/VOEvent.html Description of the VOEvent language (latest version is 1.11)]
* [http://www.ivoa.net/twiki/bin/view/IVOA/IvoaVOEvent IVOA VOEvent Working Group]
* [http://www.astronomerstelegram.org/ Astronomer's Telegrams]
* [http://www.ivoa.net/Documents/latest/STC.html Space-time Coordinate] (STC) recommendation to the IVOA