Post on 27-Mar-2015
The State of VOEvent
Rob Seaman, NOAO/DPP
IVOA InterOp, Trieste
22 May 2008
QuickTime™ and a decompressor
are needed to see this picture.
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
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
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
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
External schemata – <What>
Already in useHeliophysics 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
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)
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
Napkinrepresentation
What we signed at Hotwired in Tucson, June 2007
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>
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>
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>
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"/>
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?
A time series is an aggregate object
multiple instrumentsjoint curationcomplex footprint in time
and in space for moving objectsrequires matched calibrationsobject(s), not detections
must build associations
Orbital elements – <WhereWhen>
A targeting ephemeris
If STC can gracefully handle this, it will go a long way to resolving STC status in VO
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>
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>
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>
Alternate orbit representations
STC provides options:orbital elementsPole and pericenter vectorsRA, Decs at intervals
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>
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>
Minor tweaks?
Permit <Reference type=“kml”>
Any others?
Registering VOEvent assets
As discussed Wednesday (Thanks Roy!)
VOEventStreamScientifically coherent entity
VOEventService or VOEventServer?Logistically clustered functionality
Provides simple “schema” for <Param>
Work products
1) v2.0 standard documentv2.0 schema
2) VOEvent vocabulary (or -ies)
3) VOEvent registry documentRegistry schema
4) Pilot signing technologies
5) Transport document
6) User guide
Future events
Finalize v2.0 by the Fall InterOpHTN 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
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