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))