Search for neutrinos from gamma-ray bursts with the ANTARES telescope

1. Search for neutrinos from gamma-ray bursts with the ANTARES telescope D. Dornic for the ANTARES Collaboration

2. Neutrinos from GRBs GRBs : powerful cosmic particle accelerators producing a highly variable flux of high energy gamma-rays. Under the assumption of hadronic acceleration in jets a copious flux of neutrinos expected Among the possible astrophysical sources, GRBs offer one of the most promising perspectives for the detection of cosmic neutrinos thanks to an almost background free search. D. Dornic – Rencontres de Moriond 2009

3. ~ 100 ~ 10 Neutrinos from GRBs The Fireball model tells us how GRBs operate, but: - Which processes generate the energetic ultra-relativistic flows? - How is the shock-acceleration realized ? High energy neutrinos expected by photonuclear interactions of the observed gamma-rays with the protons accelerated by the internal shocks (typical energy above ~10 TeV) D. Dornic – Rencontres de Moriond 2009

4. GRB search techniques Triggered search Detection in conjunction with accurate timing and positional information provided by an external source Rolling search Searching for high energy or multiplet of neutrino events from the same direction and within a short time window D. Dornic – Rencontres de Moriond 2009

5. Triggered search method http://gcn.gsfc.nasa.gov/ ANTARES is a client of the GCN Special DAQ strategy D. Dornic – Rencontres de Moriond 2009

6. Triggered search method SWIFT, INTEGRAL, Fermi alerts reception ANTARES Continuous data acquisition + GRB data storage during 2 minutes without filtering D. Dornic – Rencontres de Moriond 2009

7. Triggered search method Response time to satellite triggers October 2006 – December 2008 Fermi Number of satellite triggers Swift (2008 only) Response time (s) D. Dornic – Rencontres de Moriond 2009

8. satellite triggers satellite triggered data taking number of satellite triggers date Triggered search method ANTARES GRB data taking: oct 06 – jan09 ANTARES data for 324 alerts 29 during line 1-2 period 120 during line 1-5 period 57 during line 1-10 period 118 during line 1-12 period Blinded data 24 alerts from INTEGRAL 244 alerts from Swift 56 Alerts from Fermi D. Dornic – Rencontres de Moriond 2009

9. Triggered search method • Advantages: The nature and the location of the source is known Very low background rate Low energy threshold • Disadvantages: Dependant on external sources • SWIFT (1.4 sr fov) → only ~1 / 9 GRB is detected • (no external trigger for choked GRBs) D. Dornic – Rencontres de Moriond 2009

10. GRB search techniques Triggered search Detection in conjunction with accurate timing and positional information provided by an external source Rolling search Searching for high energy or multiplet of neutrino events from the same direction and within a short time window D. Dornic – Rencontres de Moriond 2009

11. Rolling search method Search for “golden” neutrino events on-line • Advantages: • Large sky coverage • ~100 % duty cycle • No assumption on the nature of the source • Disadvantages: • the nature of the source is unknown • → need a follow-up program to confirm detection (nature, redshift…) • → need a very fast analysis with a good angular resolution D. Dornic – Rencontres de Moriond 2009

12. ΔΩ = 2° x 2° Δt = 10 min Rolling search method Multiplet of neutrino events (burst) 2 bkg events coincidence rate: Application to ANTARES: D. Dornic – Rencontres de Moriond 2009

13. ΔΩ = 2° x 2° Δt = 10 min Rolling search method Multiplet of neutrino events (burst) 2 bkg events coincidence rate: Application to ANTARES: Single neutrino event with HE Above ~20 à 50 TeV, the background rate begins to be negligible Cuts are tuned to give about 1 or 2 alerts per month D. Dornic – Rencontres de Moriond 2009

14. Rolling search method Performances of the on-line reconstruction Elevation Data : 582 MC  : 494 MC  : 13 2008 data (173 active days) D. Dornic – Rencontres de Moriond 2009

15. Rolling search method Performances of the on-line reconstruction Angular resolution Elevation Data : 582 MC  : 494 MC  : 13 2008 data (173 active days) D. Dornic – Rencontres de Moriond 2009

16. Rolling search method Collaboration with the TAROT telescope array TAROT: two 25 cm telescopes located at Calern (South France) and La Silla (Chile) - fov 1.86° x 1.86° - Magnitude V<17 (10s) V<19 (100s) - ~ 10s repositioning after the alert reception Limit: difficult association with a source in the galactic plane TAROT La Silla D. Dornic – Rencontres de Moriond 2009

17. Trigger: multiple / HE single Reconstruction “on-line” (<10ms) Alert message Neutrino telescope ν Telescope TAROT Real time Observation strategy: Real time (T0) : 6 images of 3 minutes T0+1 day, +3 days, +9 days and +27 days Rolling search method Principle D. Dornic – Rencontres de Moriond 2009

18. Rolling search method First “alert” Time: 2009-01-16 11:15:53 Zenith = 70.16° azimuth = 61.89° Representation D. Dornic – Rencontres de Moriond 2009

19. Summary and perspectives Triggered search method Special data without filtering for ~324 GRB alerts Analysis is ready & data unblinding requested within ANTARES Rolling search method By complementing neutrino telescopes with an optical follow-up, one gains significant sensitivity for transient sources. The system is operational with TAROT since two weeks. We are waiting for alerts. Would be interesting to extend technique to other wavelength (X-ray, radio). D. Dornic – Rencontres de Moriond 2009