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The State of VOEvent

The State of VOEvent. Rob Seaman, NOAO/DPP IVOA InterOp, Trieste 22 May 2008. Today’s agenda:. V2.0, time series, orbits, and all that – Rob Seaman Portfolios for Event sharing & evaluation – Matthew Graham

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The State of VOEvent

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  1. The State of VOEvent Rob Seaman, NOAO/DPP IVOA InterOp, Trieste 22 May 2008

  2. Today’s agenda: • V2.0, time series, orbits, and all that – Rob Seaman • Portfolios for Event sharing & evaluation – Matthew Graham • VO-GCN (Let the revolution begin!) – Scott Barthelmy • Resisting the forces of (unnecessary) change – Alasdair Allen

  3. Key issues are: Embracing: • Vocabularies semantically aware science • Signatures data integrity / per stream DQA • External schemata outside communities • Time series the larger time domain • Orbital elements the workflow • Registry the VO vision • Tweaks the real world

  4. Vocabularies – <What> & <Why> • As at Monday’s excellent session (& next) • Seems well in hand • No modification of standard needed • <Concept> can support controlled vocab. • <Param> can contain anything • When new vocabulary is ready, just use explicitly

  5. Signatures – envelope • As at Wednesday’s excellent session • Don’t include signature in <VOEvent> • Pick one or the other technology, or both and let the market decide • Encourage (not require) wide usage • Encourage (demand?) broker support

  6. External schemata – <What> • Already in use • Heliophysics Knowledgebase • Must be compatible with IVOA usage • Schema must support this • Registry must handle this • A small change may be needed to the language of the standard

  7. Time series vs. orbital elements • Seem similar, but very different • VOEvent is a report of observation(s) of transient phenomena,“with the implication that timely follow-up is being requested” • A time series expresses the previous sky • <What> was the behavior (thus not STC) • An orbit predicts future sky behavior • <WhereWhen> to look next time (STC)

  8. Time series – <What> • Spectral Data Model vs. “Napkin representation” • WG discussed several variations after Hotwired workshop • Make as simple as possible to start • Can elaborate in later revisions

  9. Napkinrepresentation • What we signed at Hotwired in Tucson, June 2007

  10. Time series example (per Roy & Al) <TimeSeries type="sed:Segment" version="0.1"> <Meta></Meta> <Data> <Row number="1"> <Time unit="day">1305.65557</Time> <TimeExtent unit="s">30.00002</TimeExtent> <Flux unit="mag">7.808</Flux> <FluxErr unit="mag">0.012212</FluxErr> </Row> <Row number="2"> <Time unit="day">1305.66351</Time> <TimeExtent unit="s">30.00002</TimeExtent> <Flux unit="mag">7.81995</Flux> <FluxErr unit="mag">0.012219</FluxErr> </Row> <Row number="3"> <Time unit="day">1305.6697<Time> <TimeExtent unit="s">30.00002</TimeExtent> <Flux unit="mag">7.82702</Flux> <FluxErr unit="mag">0.012232</FluxErr> </Row> </Data> </TimeSeries>

  11. Time series metadata <Meta> <PARAM name="Model" ucd="meta.id" utype="sed:DataModel" value="SED-0.95"/> <PARAM name="System" ucd="frame.pos.system" utype="sed:Segment.Frame.Sky.Type" value="FK5"/> <PARAM name="Equinox" ucd="time.equinox;pos.eq" utype="sed:Segment.Frame.Sky.Equinox" value="2000.0"/> <GROUP utype="sed:Segment.Frame.Time"> <PARAM name="TimeType" ucd="time.scale" utype="sed:Segment.Frame.Time.Type" value="MJD"/> <PARAM name="TimeZero" ucd="time;arith.zp" utype="sed:Segment.Frame.Time.Zero" value="51544.0"/> <PARAM name="TimeRefPos" ucd="time.scale" utype="sed:Segment.Frame.Time.RefPos" value="BARYCENTRIC"/> </GROUP> <GROUP utype="sed:Segment.Frame.SpectralCoord"> <PARAM name="SpectralRefPos" ucd="frame.em.system" utype="sed:Segment.Frame.SpectralCoord.RefPos" value="BARYCENTER"/> </GROUP> </Meta>

  12. Time series metadata, #2 <GROUP utype="sed:Segment.Coverage.Location"> <PARAM name="SkyPos" unit="deg" ucd="pos.eq" utype="sed:Segment.Coverage.Location.Sky.Value" value="7.47722483 8.80624972"/> <PARAM name="TimeObs" ucd="time.epoch" utype="sed:Segment.Coverage.Location.Time.Value" value="1305.6637641802704"/> <PARAM name="Instbandpass" ucd="instr.bandpass" utype="sed:Segment.Coverage.Location.SpectralCoord.Value" value="V"/> </GROUP> <GROUP utype="sed:Segment.Coverage.Extent"> <PARAM name="SkyExtent" unit="deg" ucd="instr.fov" utype="sed:Segment.Coverage.Extent.Sky" value="5"/> <PARAM name="SpectralExtent" ucd="instr.bandwidth" utype="sed:Segment.Coverage.Extent.Spectral" value="Optical"/> </GROUP> <GROUP utype="sed:Segment.Coverage.Region"> <PARAM name="TimeStart" ucd="time.expo.start" utype="sed:Segment.Coverage.Region.Time.Start" value="1305.6530292210973"/> <PARAM name="TimeEnd" ucd="time.expo.end" utype="sed:Segment.Coverage.Region.Time.End" value="1305.6744991394435"/> </GROUP>

  13. Time series metadata, #3 <GROUP utype="sed:Segment.Curation"> <PARAM name="Publisher" ucd="meta.curation" utype="sed:Segment.Curation.Publisher" value="INTA/LAEFF"/> <PARAM name="PubID" ucd="meta.ref.url;meta.curation" utype="sed:Segment.Curation.PubID" value="http://sdc.laeff.inta.es:80/omc/" /> <PARAM name="Logo" ucd="meta.ref.url" utype="sed:Segment.Curation.Logo" value="http://sdc.laeff.inta.es/omc/images/laeff-logcab-02.jpg"/> <PARAM name="Contact" ucd="meta.bib.author;meta.curation" utype="sed:Segment.Curation.Contact.Name" value="Enrique Solano"/> <PARAM name="email" ucd="meta.ref.url;meta.email" utype="sed:Segment.Curation.ContactEmail" value="esm@laeff.esa.es"/> </GROUP> <GROUP utype="sed:Segment.DataID"> <PARAM name="Title" ucd="meta.id;meta.dataset" utype="sed:Segment.DataID.DatasetID" value="OMC Light Curve. Target: AG+0849"/> <PARAM name="Instrument" ucd="inst.id" utype="sed:Segment.DataID.Instrument" value="INTEGRAL/OMC"/> <PARAM name="Creator" ucd="meta.curation.creator" utype="sed:Segment.DataID.Creator" value="INTA/LAEFF"/> </GROUP> <PARAM name="Object" ucd="meta.id;src" utype="sed:Segment.Target.Name" value="AG+0849" /> <PARAM name="Coord" unit="nm" ucd="em.wl" utype="sed:Segment.Points.SpectralCoord.Value" value="550"/> <PARAM name="Calibration" utype="sed:Segment.Points.Flux.Calibration" value="CALIBRATED"/>

  14. Time series questions • Chain of packets or embedded in single packet? • <Params> or extend the schema? or both? • VOEvent specific or general VO DM? or both? • If so, SDM or STC?

  15. A time series is an aggregate object • multiple instruments • joint curation • complex footprint in time • and in space for moving objects • requires matched calibrations • object(s), not detections • must build associations

  16. Orbital elements – <WhereWhen> • A targeting ephemeris • If STC can gracefully handle this, it will go a long way to resolving STC status in VO

  17. Orbit example <Orbit> <a unit="AU">1.5610990</a> <e>0.4412673</e> <i unit="deg">7.21282</i> <Node unit="deg">353.14214</Node> <Aop unit="deg">265.00121</Aop> <M unit="deg">319.73232</M> <T><ISOTime>1998-03-08T00:00:00</ISOTime></T> </Orbit>

  18. Orbit example, #2 <AstroCoords coord_system_id="TDB-ECLIPTIC-BARY"> <Time> <TimeInstant><ISOTime>1998-03-08T00:00:00</ISOTime></TimeInstant> </Time> <Orbit> <a unit="AU">1.5610990</a> <e>0.4412673</e> <i unit="deg">7.21282</i> <Node unit="deg">353.14214</Node> <Aop unit="deg">265.00121</Aop> <M unit="deg">319.73232</M> <T><ISOTime>1998-03-08T00:00:00</ISOTime></T> </Orbit> </AstroCoords>

  19. Orbit example, #3 <CatalogEntryLocation xmlns="http://www.ivoa.net/xml/STC/stc-v1.30.xsd” xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.ivoa.net/xml/STC/stc-v1.30.xsd http://www.ivoa.net/xml/STC/stc-v1.30.xsd"> <AstroCoordSystem xsi:nil="true" xlink:type="simple" xlink:href="ivo://STClib/CoordSys#TDB-ECLIPTIC-BARY" id="TDB-ECLIPTIC-BARY"/> <AstroCoords coord_system_id="TDB-ECLIPTIC-BARY"> <Time> <TimeInstant><ISOTime>1998-03-08T00:00:00</ISOTime></TimeInstant> </Time> <Orbit> <a unit="AU">1.5610990</a> <e>0.4412673</e> <i unit="deg">7.21282</i> <Node unit="deg">353.14214</Node> <Aop unit="deg">265.00121</Aop> <M unit="deg">319.73232</M> <T><ISOTime>1998-03-08T00:00:00</ISOTime></T> </Orbit> </AstroCoords>

  20. Alternate orbit representations • STC provides options: • orbital elements • Pole and pericenter vectors • RA, Decs at intervals

  21. Pole and vector notation: <AstroCoords coord_system_id="TDB-UNIT-ECLIPTIC-BARY"> <Time> <TimeInstant><ISOTime>1998-03-08T00:00:00</ISOTime></TimeInstant> </Time> <Position3D> <Name>P</Name> <Value3> <C1>-0.18756117</C1><C2>-0.84401876</C2><C3>-0.50243968</C3> </Value3> </Position3D> </AstroCoords> <AstroCoords coord_system_id="TDB-UNIT-ECLIPTIC-BARY" > <Time> <TimeInstant><ISOTime>1998-03-08T00:00:00</ISOTime></TimeInstant> </Time> <Position3D> <Name>Q</Name> <Value3> <C1>+0.98213469</C1><C2>-0.16897175</C2><C3>-0.08282516</C3> </Value3> </Position3D> </AstroCoords>

  22. Discrete pointings <AstroCoords coord_system_id="TDB-ICRS-BARY" > <Time> <TimeInstant><ISOTime>1998-03-18T00:00:00</ISOTime></TimeInstant> </Time> <Position2D unit="deg"> <Value2><C1>179.52</C1><C2>-3.933</C2></Value2> </Position2D> </AstroCoords> <AstroCoords coord_system_id="TDB-ICRS-BARY" > <Time> <TimeInstant><ISOTime>1998-03-23T00:00:00</ISOTime></TimeInstant> </Time> <Position2D unit="deg"> <Value2><C1>176.53</C1><C2>-7.713</C2></Value2> </Position2D> </AstroCoords> <AstroCoords coord_system_id="TDB-ICRS-BARY" > <Time> <TimeInstant><ISOTime>1998-03-28T00:00:00</ISOTime></TimeInstant> </Time> <Position2D unit="deg"> <Value2><C1>171.91</C1><C2>-13.343</C2></Value2> </Position2D> </AstroCoords>

  23. Minor tweaks? • Permit <Reference type=“kml”> Any others?

  24. Registering VOEvent assets • As discussed Wednesday (Thanks Roy!) • VOEventStream • Scientifically coherent entity • VOEventService or VOEventServer? • Logistically clustered functionality • Provides simple “schema” for <Param>

  25. Work products • v2.0 standard document v2.0 schema • VOEvent vocabulary (or -ies) • VOEvent registry document Registry schema • Pilot signing technologies • Transport document • User guide

  26. Future events • Finalize v2.0 by the Fall InterOp • HTN coordination (HTN IV) • ADASS tutorial (or BoF?) • VOEvent IV (Spring 2009?) • Activities @ IAU GA 2009? • Time domain astronomy conference @ SPIE 2010? • Many other activities continue apace

  27. Agenda: • V2.0, time series, orbits, and all that – Rob Seaman • Portfolios for Event sharing & evaluation – Matthew Graham • VO-GCN (Let the revolution begin!) – Scott Barthelmy • Resisting the forces of (unnecessary) change – Alasdair Allen

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