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

2. D. Dornic – Rencontres de Moriond 2009
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. D. Dornic – Rencontres de Moriond 2009
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 ?
~ 100
~ 10
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. D. Dornic – Rencontres de Moriond 2009
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
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. Triggered search method
ANTARES GRB data taking: oct 06 – jan09
number of satellite triggers
satellite triggers
satellite triggered data taking
date
ANTARES data for 324 alerts
29 during line period
120 during line 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. D. Dornic – Rencontres de Moriond 2009
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. D. Dornic – Rencontres de Moriond 2009
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. D. Dornic – Rencontres de Moriond 2009
Rolling search method
Multiplet of neutrino events (burst)
2 bkg events coincidence rate:
Application to ANTARES:
ΔΩ = 2° x 2°
Δt = 10 min
D. Dornic – Rencontres de Moriond 2009

13. Rolling search method Multiplet of neutrino events (burst)
2 bkg events coincidence rate:
Application to ANTARES:
ΔΩ = 2° x 2°
Δt = 10 min
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
Elevation
Angular resolution
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. D. Dornic – Rencontres de Moriond 2009
Rolling search method
Principle
Telescope TAROT ν
Neutrino telescope
Trigger: multiple / HE single
Reconstruction “on-line” (<10ms)
Alert message
Real time
Observation strategy:
Real time (T0) : 6 images of 3 minutes
T0+1 day, +3 days, +9 days and +27 days
D. Dornic – Rencontres de Moriond 2009

18. D. Dornic – Rencontres de Moriond 2009
Rolling search method
First “alert”
Time: :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