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Ground segment: PLATO Data Analysis System Laurent Gizon and PDAS Assessment Study Team Lead: MPS (Germany) and IAS (France); with contributions from Aarhus (Denmark), AIP (Germany), DLR (Germany), Cambridge (UK), LAM (France), Leicester (UK), Leuven (Belgium), MPIA (Germany) Rome, 5 May 2009 Introduction The PLATO Data Analysis System (PDAS) on the ground is in charge of the validation, calibration, and analysis of the PLATO observations. It delivers the final science data products. The PDAS comprises a Mission Operations Center (MOC, flight-critical) a Science Operations Center (SOC, mission-critical) a PLATO Data Center (PDC, science-critical) The assessment study of the PDAS benefits from extensive experience in the design of data centers for CoRoT, GAIA, Kepler, SDO, and WASP. PDAS Data Products Baseline: Light curves downloaded for all stars and all 40+2 telescopes, and ~1000 imagettes at high cadence Validated light curves (Level 0) for all stars Validated light curves and centroid curves for the 40+2 telescopes Flux calibrated light curves (Level 1) For all stars. NT flux-calibrated light curves and the centroid curves for each star, averaged over all 40 telescopes and their associated errors Two FT calibrated light curves and centroid curves for each star Data quality parameters. improved, specific for stars for which imagettes are available PDAS Data Products (cont.) Asteroseismic mode parameters For most stars Frequencies, amplitudes, and lifetimes of the modes of oscillation. From fits to spectra of stellar oscillations. Stellar rotation and stellar activity Rotation periods from activity-induced periodicities. Whenever possible, characterization of stellar activity: activity level from low-frequency power spectrum, star spot models. Stellar masses and ages For cool stars with magnitude less than 11. Stellar parameters are obtained from stellar model fits to the frequencies of oscillation Also, chemical composition etc. (seismo + spectro) PDAS Data Products (cont.) Transit candidates and their parameters List of transit candidates, List includes candidates from centroid curves (astrometry) Ranking of candidates according to planetary likelihood, Basic characteristics of the transits (depth, duration, period, and ephemerids). Planetary systems and their characteristics The most important PLATO deliverable List of confirmed planets, using follow-up observations Assessment of false alarm probability Potentially several hundreds of planetary systems for which the seismology of the central stars is possible. Determination of the planet parameters: orbital parameters, planet size, mass, density (average composition), age (from central stars) Any additional characterization of planet properties from followup observations and light curves analysis, e.g. planetary atmospheres etc. Data Products Ancillary observations: star catalog stellar parameters follow-up observations spectroscopy radial velocities interferometry astrometry (Gaia) Work Packages WP1. Project office, system architecture, archives, database, system management WP2. Science data releases, export system, data access and distribution WP3. Pipeline, workflow management system WP4. Data flow management, network WP5. Simulation of data stream (uses simul. of telemetry as input) WP6.Development of software: validation of L0 data WP7. Validation of L0 data (operational task). WP8. Software development: processing of L1 data WP9. L1 data processing (operational task). WP10. Set-up and maintain ancillary data base WP11-15 Scientific software development: Determination of asteroseismic mode parameters (WP11), Stellar rotation and stellar activity (WP12), Masses and ages of stars (WP13), Transit candidates and their parameters (WP14), Planetary systems and their characteristics (WP15) WP5 Development of software for validation of Level 0 data Validate onboard software: Validate onboard setup: Check onboard processing using ground copy of onboard software and the imagettes of ~1000 stars Validate distortion matrix model Validate 2D sky background model Validate PSF model fits Validate computation of masks and windows Fine tuning of onboard software algorithm. For example choose number of parameters needed to describe PSF. Especially during configuration mode. Monitor health of each telescope and assess quality of the data (information may have to be reported to the PDAS Steering Committee if a problem is identified) WP7 Development of software for validation of Level 1 data If required, Gain corrections Correction for jitter and residual differential aberration. Performed independently for each telescope; requires PSF knowledge, stellar catalog, and distortion matrix. Integration time correction, sampling time correction Statistical analysis over the 40 telescopes to identify cosmic ray hits, hot pixels, and possibly defectuous telescopes Average light curves and centroid curves over all telescopes (weighted average). Compute error based on scatter The ~1000 stars for which imagettes are available receive a more sophisticated treatment. PSF fits to improve photometry (contamination from neighboring sources taken into acount). Imagettes are downloaded for all stars for which a serious planetary candidate has been identified. Long term detrending PDAS Work Packages Costed in payload study ESA responsibility Partially funded through Research institutions Distribution of work: TBD with essential contributions from MPS (Germany) and IAS (France) PDAS Work Packages Mission critical (SOC) Science critical (PDC) Costed ín payload study ESA responsibility Partially funded through Research institutions PLATO Consortium Council PLATO MOC SOC Validated light curves (L0) PDC PDAS PSC PDAS Steering Committe e Users Calibrated light curves (L1) Science data products Ancillary data base (PDC likely to be distributed among a few centers) Steering Committee: takes decisions at PDAS level. One representative from each work package, instrument scientists, representative for follow-up observations, and a few specialized scientists. Users Observatories Data volumes Telemetry rate: 109 Gb/day uncompressed Over a 6 yr mission: 30 TB uncompressed The volume of archived L0, L1 and HK data is expected to be 10-50 times this amount (reformatting and calibration history), i.e. 300-1500 TB The volume of the science data products is likely to be negligible in comparison (although the complexity of the data may be high). Ancillary data base: basic stellar observations and parameters, spectra, Gaia observations, etc. The overall data volume will not exceed a few PB, which is not problematic. Time schedule January 2012. Setup of project office and start of studies June 2012. PDAS System Requirements Review June 2013. PDAS Preliminary Design Review June 2016. PDAS Critical Design Review June 2017. PDAS Flight acceptance Review December 2017: Launch of PLATO 3+2+1 years in space Several releases of science data products during and after space mission After end of mission in space: Several years of follow up observations to confirm a planet with e.g. T=3 yr. During this time the PDC must remain operational Cost 9 WPs are costed in the current study: WP1-6 and WP8-10 ~25 FTEs over 15 years (2012-2023+3) Hardware (~100 cores, PB storage), network, software: ~1 MEUR Total cost is around 30 MEUR Not costed: MOC WP7 operational task under ESA responsibility WP11-15 Scientific software development (research institutions). Resources for stellar model grid computations Conclusion The function of the PDAS is to validate and calibrate the PLATO light curves and to deliver the science data products Data volume: ~PB Compute power (L0 and L1 processing): ~100 cores The system software and hardware technologies exist today. Cost: ~30 MEUR over 2012-26 The development of the scientific software will benefit a lot from the CoRoT, Gaia, and Kepler experiences. Overall, the PDAS is relatively low-risk enterprise