high energy neutrino flux studied in the antares deep-sea telescope
DESCRIPTION
High Energy Neutrino Flux studied in the ANTARES Deep-Sea Telescope. research goals: deep cosmos the detector setup: deep sea status and performance point-source flux diffuse flux future aims summary. Herbert Löhner, KVI, University Groningen, The Netherlands - PowerPoint PPT PresentationTRANSCRIPT
H. Löhner, High Energy Neutrino Flux 1 / 17
High Energy Neutrino Flux studied in the
ANTARES Deep-Sea Telescope
Herbert Löhner, KVI, University Groningen, The Netherlandson behalf of theANTARES collaboration http://antares.in2p3.fr
• research goals: deep cosmos• the detector setup: deep sea• status and performance• point-source flux• diffuse flux• future aims• summary
H. Löhner, High Energy Neutrino Flux 2 / 17
intriguing science questions:• origin of cosmic rays 1020 eV ?• astrophysical acceleration mechanism?• origin of relativistic jets?• dark matter?
cosmic sources of neutrinos• Active Galactic Nuclei: super-massive black hole
in center of galaxies• micro quasars: X-ray binaries (in our galaxy)• supernova remnants and shock acceleration
neutrinos reach Earth undisturbed: need sensitivity and angular resolution
HESS
TeV rays (p+X 0 ) in centre of our galaxy from supernova remnant RX J1713.7-39.
Expect: p+X
p
n
neutrino astronomy
H. Löhner, High Energy Neutrino Flux 3 / 17
detection principle
νμ
µγc
θc = 43º
-ν
ν
N X
Wneutrinos can interact through charged current interactionin the vicinity of a neutrino telescope
up-going neutrinos passing through the Earth are free from atmospheric muon background
track reconstructed from Cherenkov cone passing 3D grid of PMTs
p
103 atm.
p,
107
atm. per year
cosm.
H. Löhner, High Energy Neutrino Flux 4 / 17
the telescope setup
14.5 m
~60-75 m
buoy
350 m
100 m
Junctionbox
readout cables at -2475 m
storey
3 10” PMT/storey25 storeys/line12 detection lines:~900 PMT +acoustic detection
completed May 2008
45 kmelectro-opticalcableto shore
H. Löhner, High Energy Neutrino Flux 5 / 17
up-going muon: neutrino candidatereconstruction of muon trajectory from time, charge and position of PMT hitsassuming relativistic muons emitting Cherenkov light: 34.8O up-going muon
time (ns)
he
igh
t (m
)
H. Löhner, High Energy Neutrino Flux 6 / 17
expected performance: 12 lines
angular resolution
< 0.2° above 105 GeV
limited tracking accuracy due to time resolution:
Light scattering ~ 1.0 ns TTS in PMT ~ 1.3 ns time calibration < 0.5 ns OM position < 10 cm
(↔ < 0.5 ns)
dominated by reconstruction
rec− gener.
rec−gener.dominated
by kinematics
angular resolution = difference betweenreconstructed and MC generated angles vs. neutrino energy
6.0)TeV(
º7.0
E
H. Löhner, High Energy Neutrino Flux 7 / 17
neutrino candidatesfrom track zenith distribution
5-line data (May-Dec. 2007)+ 9-12 line data (2008)
341 days detector live time,reconstruction BBfit v3r2,single- and multi-line fit:
1062 neutrino candidates:
3.1 candidates/day
elevation angle
down-goingup-going
good agreement with Monte Carlo: atmospheric neutrinos: 916 (30% syst. error) atmospheric muons: 40 (50% syst. error)
1062 cand.
H. Löhner, High Energy Neutrino Flux 8 / 17
neutrino yield per day
for some periods: high level of bioluminescence decreases reconstruction efficiency
H. Löhner, High Energy Neutrino Flux 9 / 17
performance: data rate
Median rate of measured single photon counts: typ. 60 – 80 kHzcaused by bioluminescence (~ 30 kHz) and 40K decay (~ 40 kHz) with occasional bursts of extreme high rates (~ MHz)caused by macro-organisms (depends on sea current):multidisciplinary research,oceanographic studies
H. Löhner, High Energy Neutrino Flux 10 / 17
search for point-like sources
Well reconstructed
Badly reconstructed
uncertainties inangle reconstruction: median: 0.50.1O
12-line data: 0.40.1O
absolute orientation: 0.1O
data set:2007-2008 datataken with 5, 9, 10, and 12 operating detector lines
H. Löhner, High Energy Neutrino Flux 11 / 17
coordinates of 2190 neutrino candidates
Equatorial coordinates
no significant clusters of neutrino candidates
24 source candidates
most signal-like cluster: occurs in p = 88% of
background-only experiments
H. Löhner, High Energy Neutrino Flux 12 / 17
best limits for the Southern sky
H. Löhner, High Energy Neutrino Flux 13 / 17
search for diffuse sources
( Physics Letters B 696 (2011) 16
no excess of high-energy events above expected flux from atmospheric
background from atmospheric : ~ E-3.5
cosmicneutrino models: ~ E-2
search for high-energy diffuse-flux tail
energy estimate R based on extra light fromdelayed OM hits due tohigh-energy EM showers
H. Löhner, High Energy Neutrino Flux 14 / 17
limits on diffuse neutrino flux
competitive new diffuse-flux limit,some models predicting cosmic neutrino flux can be excluded
H. Löhner, High Energy Neutrino Flux 15 / 17
Multi-Messenger astronomyStrategy: higher discovery potential by observing different probes
higher significance by coincidence detectionhigher efficiency by relaxed cuts
GCNGRB Coord. Network:γ satellites
Alerts
Ligo/VirgoGravitational waves:trigger + dedicatedanalysis chain
TAROToptical follow up:10 srepositioning
MoUs for joint research
H. Löhner, High Energy Neutrino Flux 16 / 17
future plans: KM3NeT concept
array of multi-PMToptical modules (OM)sensing Cherenkov light
instrumented volumeseveral km3
sensitive to all flavours
E > 0.1 GeV
angular resolution min 0.1o for E > 10 TeV
acceptance: up-going tracks,up to 10o above horizon
H. Löhner, High Energy Neutrino Flux 17 / 17
Summary
• ANTARES completed since May 2008• angular resolution < 0.2 degree for energies > 100 TeV• neutrino candidate events selected (3 - 5 events / day)• point sources: best limit for the Southern sky• competitive new diffuse-flux limit• multi-messenger observations on alert• KM3NeT development for several km3 observatory