Dear all,
Matteo Guainazzi (ESA-VO and XMM-Newton Archive Scientist) has compiled information on several source catalogues on different wavelengths and together with Jesus Salgado an myself we have compiled a tentative Source Catalogue Data Model, that would plug in the general Catalogue Data Model that we discussed back in Pune.
We attach a UML diagram of the model to serve as a starting point for discussion.
You will see in the model that certain of the Source specific characteristics that Matteo has identified correspond to other Data Models that are being worked by other sub-groups.
With my Catalogue DM coordinator's hat, could I ask Jonathan (for the SED) and Alberto (for the Observation/Characterisation) to cross check which of the relevant items boxed in the diagram correspond to items in their respective models? And in case they are not there, would it be possible to add them?
A small description -by Matteo- of each of the physical attributes
in the model follows together with a description by Jesus and myself
on the model itself.
The attributes' types in the model have been put for reference and
should not be taken as definitive.
Please do have a look to the Model and send your comments; this is the only way to have flexible and powerful Data Models fulfilling all the needs.
Feel free to send comments to the whole Catalogue dm group
(dm-catalog-at-ivoa.net) or, in case you send them to the general DM group
, do it with a subject containing the word [CATALOGUE] so that the rest
of DM-ers can filter properly.
Cheers,
P.
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UML diagram
Certain attributes of the Source object will, obviously, only apply to some sources (a clear example being, e.g., the visualAlbedo).
The idea of the "id" is to leave a place for specific IDs for specific projects. The standard naming for the sources should be filled in (if known) on the SIMBADName and IAUName.
Wherever STC appears, it makes reference to certain item in the Space Time Coordinate Data Model from Arnold.
Orbit is obviously only related to objects following an orbit, like binary systems. In this case, a specific object has been isolated as it might become quite big if we decide to add more specific attributes to the orbits of the objects (some of which are very well known). In this case, we have doubted whether any effort exists in the Data Model groups to describe orbits in general (Jonathan: would it need to be considered separately?).
Morphology
Orbit
STC
--- Relevant items to the Source model are specified there. Arnold should revise their validity. SED --- Jonathan should revise which of the items inside this box are present in the SED, and in case they are not, decide if they can be created. Otherwise, we might want to create an isolated object for this. Observation ----------- Alberto should revise this bit and give information (as above). AGN --- This is not an object as such. It is a place holder for any possbile AstronomicalObjects that we might want to describe in the future. We agreed in the past that in many catalogues, the type of source is either unknown or irrelevant, therefore not neededing an identification. However, other catalogues will consist, e.g., of only galaxies, for example. In this case, a Galaxy model should exist to which we could point the "type" attribute of "Source". This AGN object represents one of those future objects. Physical Description of attributes ================================== - "id": Name of the source - "IAUName": IAU name of the source - "SIMDABName": SIMBAD name of the identified counterpart - "type": Source class. It may reflect a standard object classification as in e.g.: http://simbad.u-strasbg.fr/guide/chF.htx - "coordinates": The sky coordinates of the source - "frequency": The frequency, at which the flux/magnitude/count ("flux" hereafter) measurements in the catalogue were taken - "snr": Source significance in terms of signal-to-noise ratio - "detectionProbability": Source detection probability - "distance": Distance of the source from "distanceOrigin". The cosmological redshift is a possible instantiation of this attribute - "distanceDeterminationMethod": Method employed to determine "distance". "Spectra", "Photometric", "Parallax" are possible values of this attribute - "distanceOrigin": Origin from which "distance" is being measured - "properMotion": the source proper motion on the sky vault - "radialVelocity": the radial component of the source velocity - "varAmplitude": the amplitude of the "varType" amplitude variability. It can be expressed either in physical absolute, r.m.s, or in fractional units - "varPeriod": the type of source variability: "Periodic", "Quasi-periodic", "Burst of Type I", "Aperiodic" are possible values of this attribute - "polarisatinDegree": degree of source polarization - "polarisationAngle": positional angle of the source polarization - "visualAlbedo": source visual albedo - "minorDiameter": size of the minor diameter of the source - "majorDiameter': size of the major diameter of the source - "inclination": angle between the line-of-sight to the source and the normal of the main source symmetry plane - "positionAngle": apparent position angle of the source on the sky vault - "stellarityIndex": parameter ranging from 0 (galaxy) to 1 (star), related to the probability that a given object is extended or point-like - "form": string describing the geometrical shape and/or symmetry of the source. "Boxy", "Patchy", "Ring", are possible values for this attribute - "perihelion": minimum distance from a reference point along the orbit - "perihelionTime": time of the source passing through the orbit perihelion - "afelion": maximum distance from a reference point along the orbit - "inclination": angle between the line-of-sight to the source and the normal to the plane containing the orbit - "eccentricity": fraction of the distance along the semi-major axis at which the focus lies (e=c/a, where c is the distance from the center of the conic section to the focus and a is the semi-major axis) - "positionAngle": apparent position angle of the orbit on the sky vault - "period": orbital period -- Pedro Osuna Alcalaya Software Engineer Science Archive Team European Space Astronomy CentreReceived on 2005-04-27Z14:33:25
(ESAC/ESA)
e-mail: Pedro.Osuna-at-esa.int Tel + 34 91 8131314 --------------------------------- European Space Astronomy Centre European Space Agency P.O. Box 50727 E-28080 Villafranca del Castillo MADRID - SPAIN
- application/pdf attachment: SourceDM.pdf