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Bruce Gendre Osservatorio di Roma / ASI Science Data Center PowerPoint Presentation
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Bruce Gendre Osservatorio di Roma / ASI Science Data Center

Bruce Gendre Osservatorio di Roma / ASI Science Data Center

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Bruce Gendre Osservatorio di Roma / ASI Science Data Center

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  1. Recent activities from the TAROT/Zadko network Bruce Gendre Osservatorio di Roma / ASI Science Data Center
  2. The TAROT/Zadko Network Set of 3 robotic telescopes France (20 cm diameter) Chile (20 cm diameter) Australia (1m diameter) Aims GRB studies Space debris monitoring GW source detection Variable object survey 105 GRB observed so far 21 during prompt phase 35 detections
  3. GRB 110205A GRB 110205A Swift trigger Circumpolar burst, visible all night long Redshift : 2.22 Global characteristics: Long burst T90 = 257s Spectral classification as X-ray Rich Nearly perfect follow-up Robotic telescopes (TAROT) activated during prompt phase mid-size instruments (0.5-1m) continued the follow-up for days large instruments (8+m) used at late time wide spectral coverage (far IR to X-ray)
  4. Observations Gendre et al. 2011
  5. Jet break At bin 11 X-ray and optical decay are: identical asymptotic to the same value decay index ~ 2.3 Jet effect Break is progressive p = 2.3 θ = 2.1° Gendre et al. 2011
  6. Optical flare Fast rising optical flare, not seen in X-rays Rise slope ~ t5 Peak time ~ 1000 sec Interpretation : Reverse shock in thin shell The prompt GRB and the afterglow are temporally distinct Allows calculating the Lorentz factor Γ = 125
  7. Optical flare Why this burst is unique: low density Magnetized fireball very low Lorentz factor
  8. Optical and Gamma-ray temporal correlation in the prompt very good correlation between optical and gamma-ray light curves Poor correlation between optical and X-ray light curve Optical and gamma-ray bands are due to the same mechanism ? An extra-component in X-ray ?
  9. Optical and Gamma-ray prompt spectra X-to-γ spectra require two breaks at few keV and 220 keV. Optical data do not agree with this ! Optical-Gamma ray data can be fit with the Band model But X-ray data are clearly not in agreement
  10. The model in image: GRB110205A Late internal shock Reverse shock Gendre et al. 2011 ?????! Normal afterglow Jet effect Internal shock
  11. GRB 111209A Burst detected by Swift Also observed by Konus-Wind Duration of the gamma-ray even : ~ 14 000 s Followed by XRT Sharp decay (high latitude emission) Tburst ~ 25 000 s Observation by other instruments XMM TAROT/Zadko Gendre et al., Science in prep
  12. Extra long bursts in past Long bursts usually do not last long Mean time is 20 s ! Only 5 cases with duration > 1 000 s GRB 971208 (BATSE) GRB 060814B (Konus-Wind) GRB 060218 (Swift) GRB 101225A (swift) GRB 111209A (Swift) Obvious solution: Very high redshift burst Not a real GRB Z = 10 Z = 1.0 Golenetskii et al. 2011
  13. Any other clue ? Thermal component GRB 060218 and GRB 101225A have strong thermal component GRB 111209A not However, presence of a second component in the XMM Spectrum
  14. Any other clue ? XMM-Newton spectra, 10 ks integration time, duringsteepdecay Stratta et al. In preparation
  15. Any other clue ? Thermal component GRB 060218 and GRB 101225A have strong thermal component GRB 111209A not However, presence of a second component in the XMM Spectrum Faint thermal component at high energy (> 7 keV) Power law compatible with an Inverse Compton emission from the prompt Afterglow luminosity Under luminous afterglow Compatible with the idea to radiate most of the energy in the prompt phase using only internal shocks
  16. And so ? With the data in hands, it is difficult to conclude… No host galaxy info No large follow-up despite the "Swift burst of interest" label … but we can propose some crude hypotheses A very high rotation of a giant star (see Swift J1644+57 case) ? A HMXB in a common envelop stage (with the neutron star located at the "correct" depth in the star) ? An HMXB going into the second supernovae ? Dear theoretician friends, please call me 
  17. Conclusion The TAROT/Zadko network is fine TAROT-La Silla went under refurbishment last year Zadko will move into a new building this year with a new camera and a low-resolution spectrometer Bursts are still observed GRB 110205A This is an archetypal burst with all fireball component visible and, actually, observed We need more friendly burst like this to understand the model GRB 111209A This is the longest burst ever recorded It is far less theoretician friendly But far more interesting for observing dude like me !