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
Scientific motivation
D. Dornic – ICRC 2009
GRBs:- Highly energetic gamma bursts (~1054 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
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
Principle
D. Dornic – ICRC 2009
ANTARES: 3D array of 900 OMs
Keys of success:1. High performance of the on-line reconstruction2. Good event selection
GCN alert
Triggers:Multiplet (>=2) neutrinosSingle HE neutrino
On-line reconst.
Upward-going event
TAROT South (Chile)
FOV :2° x 2°Fast pointing (10s)Good sensitivity (V<19)
Alert
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
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)
D. Dornic – ICRC 2009
Multiplet of neutrinos
1atm yrR 1000
1
ΔΩ = 3° x 3°Δt = 15 min
1atm yrR 0.005
2
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
TeVE MCmean 4
z
t
D. Dornic – ICRC 2009
Example of HE neutrinoRepresentation 2D (height/time) Representation 3D
Observation strategy
D. Dornic – ICRC 2009
GR
B a
fter
glow F ~ t-1.2
10 Minutes Cor
e-co
llap
se S
Ne
TAROT observation strategy after alert reception:Real time (T0) : 6 images of 3 minutesT0+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
Increasing luminosityDecreasing luminosityBadly substracted
Image analysis
D. Dornic – ICRC 2009
A standard image
Subtraction result
Exam
ple
(2°
x
2°)
Observations: 6 images ~2°x2° (3 min exposition)
Analysis: image subtraction (consecutive or reference)
Tuning a tool originally used for SNe identification1)Still some problems due to the very variable PSF (variable atmospheric conditions, image quality on the CCD edges, …)
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
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))