VOEvent An Information Infrastructure for Immediate Astronomical Events a Working Group of the International Virtual Observatory Alliance Roy Williams Caltech and US National Virtual Observatory 1604 image of Cas A

Event networks today IAU telegrams Astronomers Telegram Etc etc GCN service user publish subscribe observer user subscribe Natural language -- not computer usable Other providers? Extensibility? Interoperability? Eg LIGO, Pannstarrs, Palomar-Quest, SNEWS, LSST, Raptor, etc? Transport is handmade

VOEvent transport model VOEvent database VOEvent database VOEvent database user observer publish harvest subscribe user query digest (RSS) Structured, semantically rich, for machine understanding XML representation Standard transports Standard global identifiers

Pasadena VOEvent Workshop April 13/14 Alasdair Allan Exeter, UKeStars Tim AxelrodLSSTLSST Scott BarthelmyNASAGCN Vasily Belokurov Cambridge, UK Milan BogosavljevicCaltechPalomar-Quest Joshua BloomBerkeleyParitel George Djorgovski CaltechPalomar-Quest Andrew DrakePrincetonMACHO Derek FoxCaltechAstronomer’s Telegram Matthew GrahamCaltechPalomar-Quest Frederic HessmanGöttingenRTML, MONET Ashish MahabalCaltechPalomar-Quest Szabolcs Marka ColumbiaLIGO Carl PennypackerLBNLHands On Universe Paul Price HawaiiPanStarrs Arnold RotsCfA Harvard Rob SeamanNOAO Tucson Kate ScholbergDukeSNEWS, MACRO Tom Vestrand LANLRaptor Robert White LANLRaptor Roy Williams Caltech Ramon Williamson NCSA Przemyslaw Wozniak LANLRaptor

VOEvent Structure Who Publisher, Contact, etc From RTML schema? WhereWhen Can be simple eg RA, Dec, eg UTC Can be sophisticated, eg multiple frames, near objects, etc What Hierarchy of named parameters Units, Semantic type How How was the evidence gathered: camera, telescope, etc Why probability list of interpretation –supernova, comet, asteroid,..... Citation Link to other VOEvent: Followup, Supercede, Retraction, Link to support data

VOEvent Structure Event has ivo:// identifier Citation Keep it light -- no data in VOEvent-- use links Subscription / query / digest (RSS) get only the events you want –based on complex criteria –based on publisher crossmatch event libraries Transport fabric for human: , cellphone for robot: web-service, auto- , socket

Who ivo://raptor.lanl/ T14:34:16 Robert White LANL Los Alamos National Laboratory PO Box 1663 ISR-1, MS B244 Los Alamos, NM Expect users to select on publisher Schema taken from RTML….

WhereWhen Where in the sky and when? –Simple: RA, Dec in J Julian Day –Not good enough for precise positions –Sophisticated How to ease burden of interpretation Space-Time Coordinates –Where was the observer? –What about nutation? –What about surface of Mars?

WhereWhen Use IVOA Space-Time coordinate standard UTC T23:59:

What A set of named parameters, with unit, semantic type, grouping From a GCN notice GRB_INTEN: [cnts] Peak=1310 [cnts/sec] which would be expressed in VOEvent:What

Unified Content Descriptors UCD is a “semantic type” src.orbital.eccentricityOrbit eccentricity meta.code.mimeMIME type pos.gal.lonLongitude in galactic coordinates phys.at.crossSectionAtomic cross-section Can be resolved by web service –to description, examples, etc

How Raptor AB Los Alamos <Ref uri=" " type="rtml" /> Observation described by RTML document

How What do we THINK is true Fast Orphan Optical Transient NGC

VO Identifiers ivo://pq.nvo.caltech / VOEventServer # c Authority ID Registered with IVOA Resolved by registry Resource ID Resolved by registry to specific VOEvent database Record ID Not known to registry Known to event database delimiter

Distributed IVOA Registry Caltech NCSA STScI/JHU HEASARC Astrogrid CDS JapanVO IVOA registries as of Apr 05 Can resolve VOEvent identifier Redirect to specific VOEvent Database that has it ESO CfA NOAO ESAC NRAO pq.nvo.caltech I want event ivo://pq.nvo.caltech.edu -- talk to ANY IVOA registry

<VOEvent type="update" id="ivo://raptor.lanl/ /sn2005k" xmlns:stc=" xmlns:crd=" ivo://raptor.lanl/ T14:34:16 UTC T23:59: Fast Orphan Optical Transient Simplest VOEvent

Issues Initial Implementation Caltech/Berkeley/LANL/UK? as next generation GCN? Transport protocols Subscription, Digest (RSS), Query Socket, Web service, Identifiers and authorities obtaining an identifer and its persistence name resolvers Authentication of trusted publishers Aggregating related events