A.Micol IVOA Registry REGISTRY WG Mar 2003 A Science Case (and 1000 Questions) for the IVOA Registry

A.Micol IVOA Registry REGISTRY WG Mar 2003 Science Case Science Case (De Grijs) Study star cluster luminosity functions of nearby galaxies, and their dependence on the environment and evolutionary state of the host galaxy.

A.Micol IVOA Registry REGISTRY WG Mar 2003 Overall Requirement Measuring star cluster magnitudes (U, B, V, R, I, J, H) on all available archived images of nearby galaxies closer than 15Mpc, provided the resolution, field of view and exposure times are adequate.

A.Micol IVOA Registry REGISTRY WG Mar 2003 Work Plan 1) Build sample of galaxies (D < 15 Mpc) 2) Assign a galaxy type (spiral/ellipt./irreg.) to each galaxy in the sample

A.Micol IVOA Registry REGISTRY WG Mar 2003 Work Plan 3) Identify archives/telescopes/instruments able to provide: 3a) UBVRIJH fits images 3b) Adequate Field of view / Pixel scale 3c) Adequate limiting magnitude 3d) Seeing < 1.0

A.Micol IVOA Registry REGISTRY WG Mar 2003 Work Plan 4) Query the archives selected in (3) for each of the galaxies in (1) 5) Submit all necessary requests 6) Perform analysis

A.Micol IVOA Registry REGISTRY WG Mar 2003 Analysis of Requirements (1) Build sample of galaxies D < 15Mpc Which services can provide a list of nearby galaxies ? -constraint on Distance ? Which one should be used ? - the one with best quality Define Quality: -completeness of the sample ? -precision of returned measurements ? -easy to use !

A.Micol IVOA Registry REGISTRY WG Mar 2003 Analysis of Requirements (2) Assign galaxy types Is the service identified in (1) able to provide other user required attributes ? (eg, the galaxy type) If not, which other service can be used (and how) to augment the attributes of my sample ? (eg, Vizier, ADC...) Ancillary attributes (not directly required by the user) needed by subsequent services ?

A.Micol IVOA Registry REGISTRY WG Mar 2003 ASTROVIRTEL Solution (1) & (2) LEDA select name, ra, dec, type, distance from LEDA where distance < 15 Mpc Querator sends to LEDA an sql statement via an HTTP Request (POST).

A.Micol IVOA Registry REGISTRY WG Mar 2003 Registry How to identify relevant services ? Select service_name, service_description, service_interface from Registry where service_category = "object catalog" and subject = "galaxy" and querable_parameter = "galaxy distance" and output_parameter = "galaxy name" save into thisSession.catalogServices and output_parameter = "galaxy type"

A.Micol IVOA Registry REGISTRY WG Mar 2003 (3) Identify Archive/Telescopes/Instruments Suitable Archives/Telescopes/Instruments (FoV, Resolution, Wavebands, Data Types) ? ASTROVIRTEL (Querator) uses the archives known (by us and PIs) to contain data of good quality from instruments with characteristics matching the defined criteria (FOV, Resolution, Wavelength coverage).

A.Micol IVOA Registry REGISTRY WG Mar 2003 Identify Archive/Telescopes/Instruments select seviceID, instrument, mode, service_interface from Registry where service_category = "pixel_archive" and wavelength in (U,B,V,R,I,J,H,K) and limiting_magnitude > 23 and pixel_scale < 250 (mas) and field_of_view > 1 (arcmin) and data_type ="images/calibrated" Save into thisSession.archiveServices

A.Micol IVOA Registry REGISTRY WG Mar 2003 Identify Archive/Telescopes/Instruments Standard description of archives, telescopes, instruments, detectors, filters, gratings, instrument modes, etc is required Also, categories of data types must be standardised (eg image/calibrated, spectrum/raw, event_list/calibrated, etc) Metadata Registry Data Model

A.Micol IVOA Registry REGISTRY WG Mar 2003 (4) Query Submit user query to the service(s) identified in thisSession.catalogService WHO ? Results collected and sent to all archives Registry? identified in thisSession.archiveService Astronomer? VO Agent? Submission of archive requests: - user registration/authentication - the archiveService must provide a submitRequest service

A.Micol IVOA Registry REGISTRY WG Mar 2003 (4) Query Select dataset, archive From thisSession.archiveServices Where thisSession.archiveServices.objName = thisSession.catalogServices.objName Save into thisSession.datasetList

A.Micol IVOA Registry REGISTRY WG Mar 2003 (5) Submit Archival Request Foreach ( dataset, archive_id ) in thisSession.datasetList submit_request( avo_user_id, dataset, archive_id )

A.Micol IVOA Registry REGISTRY WG Mar 2003 Conclusions (before the thousand questions) What does the Registry need to solve deGrijs problem ? Metadata to describe catalogs, archives and services VO Registry Agent to bind services Data Centers to provide compliant metadata and services

A.Micol IVOA Registry REGISTRY WG Mar Questions What is a Service ? What is the Registry role ? S1. VO is an environment in which various VO services interoperate. S2. A service is an "off-the-shelf" piece of executable softwareOGC S3. A service is not a complete application (eg, Aladin is not a service). OGC S4. A service provides access to resources (being them other VO services, description of VO services, etc) S5. A service must be able to describe its contents, quality and functionality in a machine-readable way

A.Micol IVOA Registry REGISTRY WG Mar 2003 Stating the obvious ? (2) S6. A service has a well-specified interface OGC - it can only be invoked through its interface - the interface exposes the service's function to the outside world - the interface is separate from its implementation S7. A service must be able to communicate with a VO user (being it a human or a machine) using a well defined, ie standard, language(s)/protocol(s) S8. A service is interoperable, OGC - it can be invoked across networks, languages, operating systems - it is a system-independent software entity

A.Micol IVOA Registry REGISTRY WG Mar 2003 Quiz R1. A Registry is a service to handle/query metadata of other services R2. A Registry is a service to interrogate other services R3. A Registry is a service that provides interfaces to other services R4a. A Registry is a stateless service R4b. A Registry is a stateful service R5. A Registry allows for queries at different levels/depths