1. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 1 Synthesis of LoI's F. Mignard OCA/Cassiopée

2. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 2 Main Statistics 162 answers received and validated ­29 data processing in general ­7 for calibration ­10 double and multiple stars ­16 photometry ­10 planetary systems ­13 radial velocity ­8 relativity and reference frame ­5 science alerts ­12 simulations ­17 solar system objects ­20 source classification ­17 variable stars

3. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 3 Major Coordinated answers A set from Cambridge to lead the photometric processing A combined answer from Cambridge and Geneva for the science alert One answers from Geneva coordinating the involvement of ISDC One series from ARI to cover the first look, bright stars analysis Two coordinated letters from CNES covering support for simulation, major involvement in the data analysis, system architecture One global answer from Italy for a quality and validation system An international answer coordinated by Meudon for the RVS analysis One global answer from the SSWG to carry out the analysis for solar system objects

4. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 4 Answers for the Variable stars

5. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 5 Synthesis of answers Number of answers ­Collective : 6 ­Individual : 11  but some may have considered a personal reply unecessary Areas covered ­Detection of variability ­Analysis of light curves ­Period determination ­Classification ­Follow-up ­Science alert Areas marginally covered ­Simulation ­overall management

6. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 6 #instituteContactFTEAreas of interest 99Geneva Obs.G. BurkiCommitment of Geneva Obs. 45Inst. Tech. LausanneS. Morgenthaler1Statistical modelling, classification 98Geneva Obs.L. Eyer2 to 10ISDC involvement, study of variability 22CambridgeG. Gilmore1-2Detection and analysis of variables 146OHPM. Boer4Follow-up, science alert 165Univ. Cathol. LouvainC. Aerts5 ?Automated classification of lightcurves Answers to LoI : collective answers

7. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 7 #NameinstituteFTE/yrAreas of interest 2E. MiloneCalgary2-4EB : modeling, simulation 13L. SzabadosBudapest2Variable stars analysis 15Gomez de CastroMadrid?Data mining, mathematical modeling 77J. FabregatValencia0.5O-B Star classification 87P; MathiasNice0.2Light curves of Gamma Dor 111P. de LavernyNice0.5Long period Miras 113T. ZwitterLublijana0.5EB and Spectro binaries 116A. PrsaLublijana0.5Period determination, EB 145M. ChadidNice0.1Pulsating stars 149E. PorettiMilan0.2Pulsating stars 177G. GilmoreCambridge1-2Light curves and planetary transits Answers to LoI : individual answers

8. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 8 #NameinstituteFTE/yrAreas of interest 18G. GilmoreCambridge5-7S/W for the photometric processing 51A. BrownLeiden2-3Core photometric processing 94J. CarmeBarcelone2Photometric simulation, calibration 144A. Vidal MadjarParis (IAP)3 Periodic variables, micro-lensing, planetary transits 30C. Bailer-JonesHeidelberg5.5Stellar classification Related proposals

9. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 9 Organisation of the Data Processing F. Mignard From GST and DACC inputs

10. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 10 Objectives and challenges Gaia will observe over 5 years with three instruments Gaia will produce ~ 200 TB of raw data ­At the lowest level they are primarily CCD counts The DP must cope with ­A large treatment both in volume and computation ­A complex and iterative treatment ­Interconnected data and tasks It is a community task, neither organised, nor funded by ESA If must be ready by the launch time

11. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 11 Objectives and challenges It requires specific expertises and commitment : ­Overall analysis of a complex project ­Professional S/W developers ­Quality control ­Strong commitment of teams over ~ 10 to 15 years ­ Ability to work with large team under pressure with tight schedule The basic organisation does not exist yet ­This is very different from the WG structure ­The level of coordination is much more demanding ­Science will not be the primary activity in the DP ­The organisation must have clearly defined responsibilities

12. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 12 Overall Concepts There are three obvious main steps in the DP ­The initial data treatment of the CCD images up to centroiding ­The astrometric, photometric and spectroscopic iterative solution ­The special non iterative processes The global structure should be ­Must be as simple as possible ­Clear hierarchy with non overlapping responsibilities ­GST must have the full visibility and retain control of the DP The current workplan ­Global system called Gaia Data Analysis Consortium (DAC) ­Central concept around Coordination Units (CU) ­Within each CU there are Development Units (DU) ­The lower level is the Work Package (WP)

13. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 13 Coordination Units Small in number ( < 10) Each must be in charge of a significant fraction of the DP Interfaces betweens CU's are limited Each CU coordinates the developments of many tasks ­It defines the structure in DU ­It follows the development, testing and documentation of the S/W ­It defines and implement the interfaces between the DUs A CU is placed under the responsibility of a manager and his deputy ­They manage their CU ­They provide contact and interfaces with the other CUs

14. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 14 Identified Cus (provisional) C1 : Overall system architecture and central DB C2 : Data simulation ( three levels) C3 : Astrometric core processing C4 : Object processing C5 : Photometric reduction C6 : Spectroscopic reduction C7 : [Scientific exploration and Catalog access]

15. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 15 Identified Cus leaders and deputies C1 : Overall system architectureW. O'Mullane, U. Lammers C2 : Data simulation X. Luri, C. Babusiaux, F. Mignard, C3 : Astrometric core processingU. Bastian, M. Lattanzi, J. Torra C4 : Object processingD. Pourbaix, C. Bailer Jones, P. Tanga C5 : Photometric reductionF. van Leeuwen, A. Brown, C. Jordi C6 : Spectroscopic reductionD. Katz, M. Cropper, U. Munari

16. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 16 Developpement Units Responsibility for the development of S/W ­Conceptual development ­Algorithm testing on simulated data ­Preparation of the implementation of the operational versions ­Process the Gaia data and provide outputs for the DB A DU should be based on a small number of well connected groups ­Typically 5 people in each place Examples of Dus : ­PSF calibration, RV determination, orbit determination, taxonomic classification

17. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 17 Architecture and H/W Overall architecture not yet defined Several approaches possible : ­All computational H/W and DB at one place  serious funding problem ­All core processing at one place + distributed shell tasks  data transfer ­Centralised data base and core tasks ; separate location for integration of shell tasks and centralised or distributed execution ­Local data bases with shell tasks processing and coordination units

18. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 18 Astro-1: 20 TB Astro-2: 20 TB RVS : 30 TB MBP : 25 TB 50 GB/day 11h mean GS visibility per day 5 Mbps downlink rate MOC TM Archive GAIA primary Data Base Initial treatement Calibrations First look System determination (GIS) C3 C2 SimulationSimulation Data Streams Images Objects C5 Photometry C6 Spectro C4 Object Photo DBSpectro DBObject DB MBP BBP Variability Alerts Calibrations SGIS RV AP DMS Solar System Planets Galaxies QSOs Class. DB AP Age Global Class.

19. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 19 Astro-1: 20 TB Astro-2: 20 TB RVS : 30 TB MBP : 25 TB 50 GB/day 11h mean GS visibility per day 5 Mbps downlink rate MOC TM Archive GAIA primary Data Base Initial treatement Calibrations First look System determination (GIS) C3 SimulationSimulation C2 Data Streams Images Objects Photo DB C5 Photometry Spectro DB C6 Spectro Object DB C4 Object MBP BBP Variability Alerts Calibrations SGIS RV AP DMS Solar System Planets Galaxies QSOs Class. DB AP Age Global Class. Cambridge Genève CNES ESAC, UB, ISDC ? UB,CNES

20. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 20 How to form the Consortium ? Setting of a DACC (Data Analysis Coordination Committee) Must establish the structure of the consortium : ­Breakdown into CU compatible with data flow ­List of DUs within each CU ­Examine the funding issues, data flow problem, system architecture ­Identify institutes, teams or individuals for the WPs DACC established for one year ­Will be replaced by the DACE (Data Analysis Consortium Executive) An AO will be issued to formalise the structure ­no competitive AO is foreseen

21. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 21 Composition of the DACC Chair : F. Mignard Co-chair : C. Bailer-Jones CU managers : ­ W. O'Mullane, X. Luri, U. Bastian, D. Pourbaix, F. Van Leeuwen, D. Katz Project scientists : M. Perryman + Experts : A. Brown, U. Lammers, L. Lindegren, J. Torra

22. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 22 Pyramidal structure GST (includes all the CU managers) Data Analysis Consortium Executive (DACE) ­Consists of the CU managers Coordination Units ­Manager, deputy manager, S/W engineers, DUs Development Units ­Leader, includes several work packages Work Packages ­From individual to small groups within one location

23. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 23 Next Steps List of work-packages of each CU ­Compilation document in preparation Construct the data flow constraints ­Functional analysis ­List of processes and dependencies CU managers build their architecture of DUs ­Should reflect the answers to the LoI ­Large contact with the community needed Next meeting of the DACC : 6-7/10 in Heidelberg

24. Gaia, VSWG/SWG 06-08/07/05 Geneva Observatory 24 MOC: Telemetry Archive Housekeeping, Orbit Files Operations Reports Astrometry + Data Base (sample tasks in GDB) Object Tasks & Classification + Data Base Spectroscopy + Data Base (sample tasks TBD) Photometry + Data Base (position and flux information) (sample tasks in GDB) Decoding Decompression Pass Archive (flat files, t order) Spatial Ordering (HTM) Cross Matching (A/P/S) INTEGRATOR Raw Data Base [Oracle] Update LSF centroid Position + Flux Element Astrom Element Photom Match Table Source (+RV) Attitude Calibration Global Gaia Main Data Base VNVN V N-1 Source (+RV) Attitude Calibration Global Element Astrom Element Photom Match Table SAGC V N-1 Astrometric Global Iterative Solution Source Attitude Calibration Global Spectroscopic Global Iterative Solution Calibration Cross Correlation CCD/FoV/Mission ASPC results communicated via ID + parameters + data base flags + other flags 12 0 6 1818 V 0 (ground)V1V1 V2V2 GIS + shell Integrator Timeline months 8-1 weeks Gaia Data Flow, V1.1, 20-6-05 (MP, WOM, UL, LL, JdB +UB, FvL) Construct and apply Pre-pass Catalogue (V N-1 ) 1 iteration earlier Solar system objects Radial velocities Calibrated spectra Metallicity, Rotation Photometric Calibration Model Source Updating (secondary stars) AC new SGC V N-1 Image parameters Initial cross-matching On-ground att. 50 mas Cross Matching First Look Science Alerts Real-Time Attitude (~6 arcsec) PSF/LSF calibration CCD calibration A/P/S calibration Heidelberg ASM imaging (disturbing stars) Reference Frame Photometric Calibration Parameters Photometric Calibration Stars Visual binaries Astrometric binaries Planets Source classification Astrophysical parameters Calibration MonitoringReduced photometric data Epoch photometry Constant stars Accumulating statistics Variability analysis Period type? No: Unsolved variables Period search Period type? Yes: Periodic variables Alert filter Unexpected change in brightness/classification Alerts: SNe, NEO ESAC Cambridge ? CNES? ESAC Lund, BarcelonaCambridge, Leiden, Geneva Meudon, MSSL ESAC Heidelberg, Bruxelles, Paris

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