CPPM: M. Ageron, I. Al Samarai, V. Bertin, J. Brunner, J. Busto, D. Dornic, S. Escoffier

IRFU: B. Vallage

LAM: S. Basa, B. Gendre, A. Mazure

TAROT: M. Boer, A. Le Van Suu (OHP), A. Klotz (CESR)

Scientific motivations

Detection of transient sources such as:- Gamma Ray Bursts- Core Collapse Sne- AGNs- Microquasars- …

Observed in many wavelengths (X, visible…)Potential neutrino emitters

So far, only 1 detection of extrasolar neutrinos : SN1987A

Microquasar luminosity vs time

Scientific motivations

Some of the most interesting:

GRBs:- Highly energetic gamma bursts (~1051 ergs)- Observed at a rate <1 per day with gamma satellites- Other detections are triggered by a satellite alert (Optical

telescopes, neutrino telescopes…)

Failed GRBs:- Not visible in gamma but potentially neutrino emitters- How to trigger a detection for such objects?

Rate of local GRBs << SN rate

The GRBs/SNe Connection

Rate of local GRBs << SN rate Core Collapse SNe : jets with different velocities:

Highly relativistic GRBs () Mildly relativistic « Failed GRBs » (few%) (hidden in gamma)

The GRBs/SNe Connection

In « failed GRBs »:• No gamma counterpart• Still, protons are acceleratedp-p interaction MesonsMesons decay into neutrinos

Ando & Beacom (PRL 95,061103(2005))Razzaques, Meszaros,waxman(PRL 93,181101(2004))(PRL 94, 109903(2005))

Expected neutrino flux from a FGRB in ANTARES

In « failed GRBs »:• No gamma counterpart• Still, protons are acceleratedp-p interaction MesonsMesons decay into neutrinos

Antares threshold

Ando & Beacom (PRL 95,061103(2005))Razzaques, Meszaros,Waxman (PRL 93,181101(2004))(PRL 94, 109903(2005))

Expected neutrino flux from a FGRB in ANTARES

•For the Multiplet (>= 2 neutrinos) trigger: Horizon at 10 Mpc

When applying HE event conditions, •For 1 HE neutrino: Horizon at 1 Mpc

For 1 SNe

LE events

The Multiplet trigger can push the horizon of detection further than the HE event trigger does

HE events

ANTARES: 900 PMTs

- TAROT Sud (Chili)

- FOV :2° x 2°- Fast repositioning (10s)- Good sensitivity (V<19)

Idea: Optical detection of transient sources triggered by ”special” neutrino events.

Main advantage: covers the full hemisphere

Keys of success:1. High performance of the online reconstruction2. Good event selection

GCN alert

Triggers:Multiplet of neutrinosSingle HE neutrino Alert

On-line reconstruction

Upward-going event

ANTARES: 900 PMTs

- TAROT Sud (Chili)

- FOV :2° x 2°- Fast repositioning (10s)- Good sensitivity (V<19)

Median Angular resolution vs energy

Angular resolution as good as 0.5° for highest energetic events

•A very fast algorithm is needed Reconstruction taking 10ms / event is implemented•The better is the reconstruction angular resolution the easier it is to find the source in the image analysis phase

Reconstruction on at least 3 detector lines required to avoid mirror solutions

Trigger: Doublet of neutrinos

A detection would be have 3 significance

1atm yrR 300

1

ΔΩ = 3° x 3°Δt = 15 min

1atm yrR 0.007

2

Background estimation: High energy eventsBackground: Dominated by atmospheric neutrinos

Median Ang. Res.~ 0.75°

E moy ~4 TeV

After cuts on energy estimators:

MC

Seen on at least three detector lines

The TaToO projectKeys of success (2/2)

Event selection

High energy eventsBackground: Dominated by atmospheric neutrinos

Median Ang. Res.~ 0.75°

E moy ~4 TeV

After cuts on energy estimators:

MC

Tuned actual cuts to send 1 to 2 alerts/ month to TAROT; mostly would be from HE

trigger

The TaToO projectKeys of success (2/2)

Event selection

Number of hits used in track fit

Total amplitude

2008 data

2008 data

z

t

Example of HE neutrinoRepresentation 2D (height/time) Representation 3D

GR

B

aft

erg

low

F ~ t-1.2

10 Minutes

Core

-colla

pse

S

Ne

Two promising source classes for this detection:

TAROT observation strategy after alert reception:Real time (T0) : 6 images of 3 minutes

T0+1 day, +3 days, +9 days and +27 days This detection strategy is appropriate to follow the main objects time profile and to allow a reasonable time for image analysis

The Observation strategy

A standard image

Subtraction result

Still to be done:1) Test the subtraction algorithm: some problems due to the very variable

PSF (variable atmospheric conditions, image quality on the CCD edges)2) Include the tool in an automatic system

Exam

ple

Increasing luminosityDecreasing luminosityBadly substracted

Tuning a tool originally used for SNe identification

TAToO is a promising detection tool of transient sources using neutrino telescopes as a trigger

This is the only method to detect satellites hidden sources as FGRBs

Several alerts sent already to Tarot Image analysis tools are studied In the future, this system is intended to be coupled

with other detectors (Rotse, Swift, ATA…)