1. Search for neutrinos from transient sources with the ANTARES telescope and optical follow-up observations 31st International Cosmic Ray Conference Lodz 7-15/07/2009 D. Dornic (CPPM/IN2P3/CNRS, France) On behalf of the ANTARES and TAROT Collaborations

2. Scientific motivation D. Dornic – ICRC 2009 GRBs: - Highly energetic gamma bursts (~10 54 ergs) - Observed at a rate ~1 per day with gamma satellites - Neutrino detection based on the trigger provided by a satellite alert Failed GRBs: - Not visible in gamma but potentially neutrino emitters - Up to now, only a model !!! - How to trigger a detection for such objects? Razzaques, Meszaros,waxman PRL93,181101(2004) & PRL 94, 109903(2005) Ando & Beacom PRL 95,061103(2005) May be, the most interesting for neutrino searches: M. Bouwhuis, poster 0G 2.4

3. Principle D. Dornic – ICRC 2009 ANTARES: 3D array of 900 OMs TAROT South (Chile) FOV :2° x 2° Fast pointing (10s) Good sensitivity (V<19) Idea: Optical detection of transient sources triggered by ”special” neutrino events. Main advantage: covers the full hemisphere, very large duty cycle

4. Principle D. Dornic – ICRC 2009 ANTARES: 3D array of 900 OMs Keys of success: 1. High performance of the on- line reconstruction 2. Good event selection GCN alert Triggers: Multiplet (>=2) neutrinos Single HE neutrino On-line reconst. Upward-going event TAROT South (Chile) FOV :2° x 2° Fast pointing (10s) Good sensitivity (V<19) Alert

5. D. Dornic – ICRC 2009 Radius of the error box of the alert position can reach 0.5°- 0.7° for the best reconstructed and highest energy events A very fast algorithm → < 1s / event for the reconstruction, the trigger and the alert sending. The better is the angular precision of the pointing → the easier it is to find the source in the image analysis phase Median Angular resolution vs energy On-line reconstruction A. Heijboer, talk 13/07 15h30 0G 2.5

6. D. Dornic – ICRC 2009 A very fast algorithm → < 1s / event for the reconstruction, the trigger and the alert sending. The better is the angular precision of the pointing → the easier it is to find the source in the image analysis phase On-line reconstruction Error box of the alert position (median)  Real time: 0.5-0.7°  After few hours: 0.4-0.5° (standard ANTARES reconstruction program)  After a week: 0.2-0.3° (with the full dynamical line geometry)

7. D. Dornic – ICRC 2009  Multiplet of neutrinos ΔΩ = 3° x 3° Δt = 15 min Background estimation:  Single high energy events ➜ Selection of high energy events  Tuned actual cuts to send 1 to 2 alerts/ month to TAROT; mostly would be from HE trigger Event selection ➜ A detection would be almost significant Background: Dominated by atm. neutrinos

8. z t D. Dornic – ICRC 2009 Example of HE neutrino Representation 2D (height/time) Representation 3D

9. Observation strategy D. Dornic – ICRC 2009 GRB afterglow F ~ t -1.2 10 Minutes Core-collapse SNe TAROT observation strategy after alert reception: Real time (T 0 ) : 6 images of 3 minutes T 0 +1 day, +3 days, +9 days and +27 days  Appropriate to follow the transients time profile and to allow a reasonable time for image analysis

10. Increasing luminosity Decreasing luminosity Badly substracted Image analysis D. Dornic – ICRC 2009 A standard imageSubtraction result Example (2° x 2°) Observations: 6 images ~2° x 2° (3 min exposition)  Analysis: image subtraction (consecutive or reference) Tuning a tool originally used for SNe identification 1)Still some problems due to the very variable PSF (variable atmospheric conditions, image quality on the CCD edges, …)

11. D. Dornic – ICRC 2009  TAToO is a promising detection tool of transient sources using neutrino telescopes as a trigger  This is the only method to directly detect hidden sources such as Failed GRBs  Few alerts have been sent  In the future, this ANTARES follow-up will be extended to include other instruments (Swift, ATA…) Summary

13. Neutrino from failed GRB D. Dornic – ICRC 2009 For 1 SNe LE events HE events Expected neutrino signal Using estimation: 1 Core collapse SNe/ yr/ 10 Mpc ➜ 0.4 SNe detected per year in ANTARES Protons accelerated in midly relativistic jet (Г~3) p-p interaction → Mesons → Neutrinos Ando & Beacom model (PRL 95,061103(2005))