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TAROT (Télescope à Action Rapide pour les Objets Transitoires)

TAROT (Télescope à Action Rapide pour les Objets Transitoires). Michel Boër CNRS – Observatoire de Haute Provence. Les sursauts gamma (GRB). Une explosion rapide suivie d’une décroissance graduelle Evènement prompt Détecté en gamma par les satellites Dure de 0.01 à 1000s

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TAROT (Télescope à Action Rapide pour les Objets Transitoires)

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  1. TAROT(Télescope à Action Rapide pour les Objets Transitoires) Michel BoërCNRS – Observatoire de Haute Provence

  2. Les sursauts gamma (GRB) • Une explosion rapide suivie d’une décroissance graduelle • Evènement prompt • Détecté en gamma par les satellites • Dure de 0.01 à 1000s • 2 populations (0.5s et 30s) • Partie rémanente, décroissante en t-1,-2 • ~ 2 GRB/j >10-8erg/s.cm-2 .4πSter • SWIFT 150/an, GLAST 400/an • Taux local ~2 Gpc-3 yr-1 • Evènements Panchromatiques: • Emission maximale entre < 10 and 1000 keV • Détectés entre 1mkeV to >? 20 GeV) • Très variables (< 10ms) • Origine cosmologique (0,001 < z < 6,29 (measured) < 15??) • Très lumineux: 1051-52ergs (mais émission en jets) M. Boer, OHP

  3. 1016 cm 1013 cm g RB 106 cm G2 Emission rémanente G1 t-1 tGRB taft Le modèle de la boule de feu M. Boer, OHP

  4. Une chaîne pour la détection HETE position 8s VHF 0,5s INTERNET Pointageobservation(1s) M. Boer, OHP

  5. Tarot today M. Boer, OHP

  6. A fully automated telescope M. Boer, OHP

  7. Automated correlation with USNO catalogAutomated image comparison for variable objects Data processing (see A. Klotz) M. Boer, OHP

  8. TAROT & SWIFT M. Boer, OHP

  9. SWIFT GRBs observed by TAROT M. Boer, OHP

  10. GRB 050904 • Event at 01:51:44 • T90 = 225s • First image at 01:53:10 (TAROT reaction time 4s) 86s after event started • Last at 1666s • First images stacked to increase sensitivity • Field observations performed at OHP to calibrate frames M. Boer, OHP

  11. GRB 050904 & GRB 990123 • Plateau observed for GRB 050904 may have been missed for GRB 990123 because of dead-time • Plateau + flare: how to explain them within context of refreshed shock or reverse shock? • For the future need of better sampling and less dead time • Luminosity of GRB 050904 (1054erg) comparable to GRB 990123 (2.4 x1054erg) • Behavior of both events quite similar • Suggest class of optically bright OTs • May be used for detection up to very high redshifts even with small / moderate telescopes • Allow fast, 1s, sampling and easier spectroscopy • Should be confirmed by other events: TAROT data suggest that other events may be bright OTs (050505 & 050730) • Recent work (Gendre et al. 2006) shows evidences for a fireball expanding in the early wind of a massive star: observation of a star at z = 6.29 M. Boer, OHP

  12. Sensitivity vs. continuous imaging • Tracked drift mode • Drift mode at 3.33 s/pixel rate • Drift image lasts 60s, i.e. 18 pixels of continuous monitoring • Following images are non-trailed (sidereal tracking on), 30 to 180s, 5s dead-time • For GRB 060111b, USNO star used as comparison M. Boer, OHP

  13. The light curve • GRB 060111b • 20:15:43 UT • Close to the Moon • No redshift available but • UVOT detection (5min), z < 3 • B&G relation gives z = 2, but invalid if z < 0.5 • Continuous monitoring from 28 to 88s • From 28 to 61, sampling = 1px = 3.33s, after binning over 4pix = 13.3s • Smooth! • Continuous, fast decay from Ttrig + 28 to 90s: 2.4 • No evidence of flare at time of gamma-ray second peak • Then shallower decay 1.12, typical AG • If 1 component, Tbreak = 80s • If 2 component: • Alpha1 = 3.0 • Alpha2 = 0.89 • Ttrans = 65s ! M. Boer, OHP

  14. TAROT: a versatile telescope • In summary • A relatively sensitive instrument • Wide field • Designed for variable objects • Large availability, advanced scheduler • Versatile, very easy to use • One of the rare fully automated telescopes • Full autonomus operations, supervision possible • Advanced scheduler, multi purpose (e.g. satellites, stars, GRB, periodic…), now multi-telescope • On-line data processing, automatic search for variable and transient objects • Archiving and automatic transfer • Immediate results and images availability on the web • Immediate dissemination of transient position (web, e-mail, sms) M. Boer, OHP

  15. Scientific programs • Variable star catalog • All fields were searched for variable • Catalog of 2000 objects being published • Fully automated blind search • Specific objects (RR Lyr) • Supernovae • AGNs • Solar system objects (binary asteroids…) • Orbital environment (satellites and debris) M. Boer, OHP

  16. TAROT variable star catalog(Damerdji, Klotz and Boër, 2006) M. Boer, OHP

  17. Present and future • Enhance archiving and data acces • New release of automation program • Now, automated dissemination of results • TAROT-Chili is being installed at La Silla • Work with 2 telescopes in synchrone mode, another telescope planned (Australia) • Within the framework of SVOM/ECLAIRs, OHP leads the team for the 1.50m follow-up telescope M. Boer, OHP

  18. TAROT experience for ASTEP • TAROT has becomed a very efficient instrument • Though small, able to give cutting edge scientific results • Experience gained in automated instruments • TAROT are non-attended instruments • System approach • Reliable hardware (specific opto-mechanical design, control/command) • Reliable software • Failure rate very low (i.e. high efficiency) • Advanced scheduling (multi-telescope) • Automated processing and archiving • Diverse types of requests • Now advanced scheduler for both instruments • This experience can be transfered to ASTEP M. Boer, OHP

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