Search for neutrinos from gammaray bursts with the ANTARES telescope

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Search for neutrinos from gamma-ray bursts with
the ANTARES telescope
D. Dornic for the ANTARES Collaboration
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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.
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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)
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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
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Triggered search method
http//gcn.gsfc.nasa.gov/
ANTARES is a client of the GCN
Special DAQ strategy
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Triggered search method
SWIFT, INTEGRAL, Fermi alerts reception
ANTARES
Continuous data acquisition

GRB data storage during 2 minutes without
filtering
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Triggered search method
Response time to satellite triggers
October 2006 December 2008
Fermi
Number of satellite triggers
Swift (2008 only)
Response time (s)
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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
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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)

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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
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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
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Rolling search method
Multiplet of neutrino events (burst)
2 bkg events coincidence rate
Application to ANTARES
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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
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Rolling search method
Performances of the on-line reconstruction
Elevation
Data 582 MC ? 494 MC ? 13
2008 data (173 active days)
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Rolling search method
Performances of the on-line reconstruction
Angular resolution
Elevation
Data 582 MC ? 494 MC ? 13
2008 data (173 active days)
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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 Vlt17 (10s)
Vlt19 (100s) -
10s repositioning after the alert
reception Limit difficult association with a
source in the galactic plane
TAROT La Silla
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Rolling search method
Principle
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Rolling search method
First alert
Time 2009-01-16 111553 Zenith
70.16 azimuth 61.89
Representation
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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).