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 …

Microquasar luminosity vs time

 Observed in many wavelengths (X, visible…)  Potential neutrino emitters  So far, only 1 detection of extrasolar neutrinos : SN1987A

Scientific motivations

Some of the most interesting: -

GRBs:

Highly energetic gamma bursts (~10 51 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?

The GRBs/SNe Connection

 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)

Expected neutrino flux from a FGRB in ANTARES

In « failed GRBs »: • No gamma counterpart • Still, protons are accelerated  p-p interaction  Mesons  Mesons 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

Antares threshold

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

Ando & Beacom (PRL 95,061103(2005))

Razzaques, Meszaros,Waxman

(PRL 93,181101(2004)) (PRL 94, 109903(2005))

For 1 SNe

LE events HE events •

For the Multiplet (>= 2 neutrinos) trigger:

 Horizon at 10 Mpc

When applying HE event conditions,

•

For 1 HE neutrino:

 Horizon at 1 Mpc 

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



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



Main advantage:

covers the full hemisphere

-

TAROT Sud (Chili) FOV :2 °

x 2

° Fast repositioning (10s)

Good sensitivity (V<19)

ANTARES: 900 PMTs

Triggers: Multiplet of neutrinos Single HE neutrino 

Alert Keys of success: 1.

High performance of the online reconstruction

2.

Good event selection

Upward-going event

ANTARES: 900 PMTs

On-line reconstruction

-

TAROT Sud (Chili) FOV :2 °

x 2

° Fast repositioning (10s)

Good sensitivity (V<19) GCN alert

• 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  Angular resolution as good as 0.5

° for highest energetic events Median Angular resolution vs energy

The TaToO project

Keys of success (2/2) Event selection 

Trigger: Doublet of neutrinos Background estimation:

R

1

atm

 300

yr



1

Seen on at least three detector lines ΔΩ = 3 ° x 3 ° Δt = 15 min

R

2

atm

 0.007

yr



1



High energy events Background:

Dominated by atmospheric neutrinos After cuts on energy estimators: MC 

A detection would be have 3



significance E moy ~4 TeV Median Ang. Res.~ 0.75

°

The TaToO project

Number of hits used in track fit 2008 data Keys of success (2/2) Event selection 

High energy events Background:

Dominated by atmospheric neutrinos After cuts on energy estimators: MC Total amplitude 2008 data

E moy ~4 TeV Median Ang. Res.~ 0.75

°



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

Example of HE neutrino

Representation 3D Representation 2D (height/time)

z t

The Observation strategy

Two promising source classes for this detection: F ~ t -1.2

10 Minutes

TAROT observation strategy after alert reception: Real time (T 0 ) : 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

Tuning a tool originally used for SNe identification

Increasing luminosity Decreasing luminosity Badly substracted

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

     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…)