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

Search for neutrinos from gamma-ray bursts

with the ANTARES telescope

D. Dornic for the ANTARES Collaboration

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.


Neutrinos from GRBs

~ 100 ~ 10

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)


GRB search techniques

Detection in conjunction with accurate timing and positional information provided by an external source

Triggered search

Rolling search

Searching for multiplets of neutrino events from the same direction and within a short time window


Triggered search method

Special DAQ strategy

ANTARES is a client of

the GCN

http://gcn.gsfc.nasa.gov/



ANTARES

SWIFT, INTEGRAL, Fermi alerts reception

GRB data storage during 2 minutes without filtering

Standard acquisition

+


Triggered search methodResponse time to satellite triggers

October 2006 – December 2008

Response time (s)

Num

ber

of s

atel

lite

trig

gers

Fermi

Swift (2008 only)


num

ber

of s

atel

lite

trig

gers

satellite triggers

satellite triggered data taking

date


Blinded data

ANTARES GRB data taking: oct 06 – jan09

24 alerts from INTEGRAL244 alerts from Swift56 Alerts from Fermi

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



Advantage: The nature and the location of the source is known

Very low background rate

Low energy threshold

Disadvantages: Depend on external sources

SWIFT (1.4 sr fov) → only ~1 / 9 GRB is detected no external trigger for choked GRBs)


GRB search techniques

Detection in conjunction with accurate timing and positional information provided by an external source

Triggered search

Rolling search

Searching for multiplets of neutrino events from the same direction and within a short time window


Rolling search methodSearch for “special” neutrino events on-line

Advantage: Large sky coverage

~100 % efficientNo 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


Rolling search methodMultiplet of neutrino events (burst)

Cuts are tuned to give around 1 or 2 alerts per month

Single neutrino event with HE

212 22 atmatm RtR

11 1500 yrR atm

ΔΩ = 2° x 2°

Δt = 10 min

12 01.0 yrR atm

2 events coincidence rate: Application to ANTARES:

Above ~20 à 50 TeV, the background rate begins to be

negligible


sin(θ)

Rolling search method

On-line reconstruction for the 10 lines detector

Elevation

Data : 307MC : 271MC : 7

Angular resolution



Collaboration with the TAROT telescopes 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 receptionLimit: difficult association with a source in the galactic plane

TAROT La Silla



Telescope TAROTν

Neutrino telescope

Trigger: multiple / HE single Reconstruction “on-line” (<10ms)Alert message

Real time

Principle

Observation strategy:Real time (T0) 6 images of 3 minutes

T0+1 day, +3 days, +9 days and +27 days



First alert

Time: 2009-01-16 11:15:53.00 Zenith = 70.16 azimuth = 61.89

Representation


Summary and perspectives

Special data without filtering for ~324 GRB alertsAnalysis is ready & unblinding requested


By complementing neutrino telescopes with an optical follow-up, one gains significant sensitivity for transient sources.

The system is operational with TAROT since one week. We are waiting for alerts.

Interesting to extend technique to other wavelength (X-ray, radio).


Documents

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