190 likes | 333 Views
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) * TAToO Coordinator. Imen Al Samarai
E N D
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) * TAToO Coordinator Imen Al Samarai CPPM-ANTARES team
Scientific motivations Been observed in many wavelengths (X, radio…) Potential neutrino emitters and can be followed by optical telescopes GRB afterglow
Scientific motivations One 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?
The SN/ GRB Connection • Rate of local GRBs << SN rate Credit: S. ANDO gwhen 2009
The SN/ GRB Connection • Rate of local GRBs << SN rate • Core Collapse SNe : jets with different velocities: • Highly relativistic GRBs () • Mildly relativistic « Failed GRBs » (few%) Credit: S. ANDO gwhen 2009
Expected neutrino flux from a FGRB in ANTARES In « failed GRBs »: • No gamma counterpart • Still, protons are accelerated • p-p interaction (p,k ) • 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 The expected neutrino flux in the ANTARES effective surface gives 2 neutrino events > 100GeV from a FGRB at 10 Mpc In « failed GRBs »: • No gamma counterpart • Still, protons are accelerated • p-p interaction (p,k ) • Mesons decay into neutrinos Antares threshold Ando & Beacom (PRL 95,061103(2005)) Razzaques, Meszaros,waxman (PRL 93,181101(2004)) (PRL 94, 109903(2005))
Idea: Optical detection of transient sources triggered by ”special” neutrino events. • Main advantage: covers the full hemisphere • TAROT Sud (chili) • FOV :2° x 2° • Repositionnement rapide (10s) • Bonne sensibilité (V<19) ANTARES: Réseau tridimensionnel de 900 PMs
Triggers: Multiplet (>=2)neutrinos Single HE neutrino Alert Keys of success: 1. High performance of the online reconstruction 2. Good event selection Upward-going event GCN alert • TAROT Sud (chili) • FOV :2° x 2° • Repositionnement rapide (10s) • Bonne sensibilité (V<19) On-line reconst. ANTARES: Réseau tridimensionnel de 900 PMs
Triggers: Multiplet (>=2)neutrinos Single HE neutrinoAlert Keys of success: 1.High performance of the online reconstruction 2. Good event selection Upward-going event GCN alert • TAROT Sud (chili) • FOV :2° x 2° • Repositionnement rapide (10s) • Bonne sensibilité (V<19) On-line reconst. ANTARES: Réseau tridimensionnel de 900 PMs
Median Angular resolution vs energy Angular resolution can go down to a radius of 0.5° for best reconstructed and highest energy events • A very fast algorithm is needed Reconstr. 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
Triggers: Multiplet (>=2)neutrinos Single HE neutrino Alert Keys of success: 1. High performance of the online reconstruction 2. Good event selection Upward-going event GCN alert • TAROT Sud (chili) • FOV :2° x 2° • Repositionnement rapide (10s) • Bonne sensibilité (V<19) On-line reconst. ANTARES: Réseau tridimensionnel de 900 PMs
s Background estimation: • Multiplet of neutrinos R1 atm = 1000 yr-1 in ANTARES For a doublet: ΔΩ = 3° x 3° R2 atm ~0.005 yr-1 Δt = 15 min Lower for a triplet, .... • A detection would be almost significant • High energy events Background: • Dominated by atm. neutrinos After cuts on energy estimators: MC Emoy ~4 TeV • Tuned actual cuts to send 1 to 2 alerts/ month to TAROT; mostly would be from HE trigger
Triggers: Multiplet (>=2)neutrinos Single HE neutrinoAlert Keys of success: 1. High performance of the online reconstruction 2. Good event selection Upward-going event GCN alert • TAROT Sud (chili) • FOV :2° x 2° • Repositionnement rapide (10s) • Bonne sensibilité (V<19) On-line reconst. ANTARES: Réseau tridimensionnel de 900 PMs
The observation strategy TAROT observation strategy after alert reception: Real time (T0) : 6 images of 3 minutes The real time treatment of the alert will depend on the availability of the telescope (may be delayed by few minutes) T0+1 day, +3 days, +9 days and +27 days These four steps are just indicative and depend on the availability of the telescope This detection strategy is appropriate to follow the main objects time profile and to allow a reasonable time for image analysis
Still to be done:Include the tool in an automatic system Tuning an image substraction program originally used for SNe Search Increasing luminosity Decreasing luminosity Badly substracted Example A standard image Subtraction result
TAToO trigger evaluation for FGRBs detection • The Multiplet trigger can push the distance of detection further than the HE event trigger does • For the Multiplet • (>= 2 neutrinos) trigger: • Detection around 4 Mpc When applying HE event conditions, • For 1 HE neutrino: Detection around 1 Mpc According to the neutrino flux model from FGRBs Ando & Beacom (PRL 95,061103(2005))
Expected rate of FGRBs detectable with the multiplet trigger Using estimation : 1 Core collapse SNe/ yr in a sphere radius of 10 Mpc Ando, Beacom &Yuksel(PRL 95,171101(2005)) ~ 0.015 SN/ yr @ 4 Mpc • Cumulated to 4 Mpc, • 0.06 Cc SN /yr would be detectable • with the multiplet trigger • in ANTARES This rate is a lowerlimit: canbetripledconsidering the truenearbyCore -collapse SNe rate According to the model, ANTARES (multiplet trigger) would expect a FGRB detection within ~ 5 years
TAToO is a promising project for the detection of transient sources using neutrino telescopes as a trigger • It is very interesting for the detection of satellites hidden sources such as FGRBs • Trying to ameliorate ang. Resolution down to 0.3° • First alert on sat. 27/06 • In the future, this system is intended to be coupled with other detections (swift, ATA…)