Transcript KM3NeT IceCube

Connections IceCube – KM3NeT
Christian Spiering
DESY
Content
• Lessons from IceCube
•
•
•
•
„Multi-wavelength“ point source searches
Network of Target of Opportunity projects
Other coordinated efforts
Cooperation on software and algorithms
• Formal questions
Lessons from IceCube (and from theoreticians)
• How big a detector ?
• Optimization to which energy range ?
• Which configuration ?
How big a detector ?
• KM3NeT: „Substantially more sensitive than IceCube“
• Point sources: factor ~2 from angular resolution alone
• This is by far not enough in case IceCube would not have
identified sources in 2010/11
• Need something like the „canonical factor 7“
– LHC  LHC upgrade (in luminosity)
– 50 kt Super-K  300 kt DUSEL/Hyperkam (in volume)
– Auger-South  Auger North (in area)
•  Need much more than a cubic kilometer in volume !!
Early IceCube spacing exercises
• Increasing the string
spacing from 100 to 180 m
increases:
IceCube: 125 m
– volume by factor 3
– 5 sensitivity by 40%
• We have been reluctant to
go to the largest spacing
since:
– String-to-string calibration may work
worse.
– Due to light scattering in ice the
sensitivity increases much weaker
than the area for large spacing.
– We were optimistic w.r.t. the signal
expectation.
E-2
Early IceCube spacing exercises
• Increasing the string
spacing from 100 to 180 m
improves:
IceCube: 125 m
– volume by factor 3
– 5 sensitivity by 40%
• We have been reluctant to
go to the largest spacing
since:
– String-to-string calibration may work
worse.
– Due to light scattering in ice the
sensitivity increases weaker than
the area for very large spacing.
– We were optimistic w.r.t. the signal
expectation.
Would be no concern today
Not important in water
Too optimistic
Threshold for best sensitivity
1 cubic kilometer IceCube
Diffuse E-2 flux
Blue: after downgoing muon rejection
Red: after cut for ultimate sensitivity
Threshold for best sensitivity
1 cubic kilometer IceCube
Point sources (E-2)
Blue: after downgoing muon rejection
Red: after cut for ultimate sensitivity
Threshold for best sensitivity
Several cubic kilometers
Point sources
(educated guess)
Threshold between
3 and 5 TeV !
Blue: after downgoing muon rejection
Red: after cut for ultimate sensitivity
Ceterum censeo:
• Optimize to energies
> 5 TeV, even if you
have to sacrifice lower
energies!
208m
624m
• See original GVD/Baikal with
muon threshold ~ 10 TeV
(but, alas, < 1 km³)
70m
280
m
12
0m
70
m
Expected n flux from galactic point sources,
example: RXJ 1713-3946 (see also Paolo Lipari’s talk)
Assume p0  g and calculate related p±  n
C. Stegmann
ICRC 2007
Milagro sources in Cygnus region
Halzen, Kappes, O’Murchadha
Probability for
fake detection:
•
6 stacked sources
•
Assumption: cut-off at 300 TeV
•
p-value <10-3 after 5 years
•
Optimal threshold @ 30 TeV
(determined by loss of signal events)
Aharonian, Gabici etc al. 2007
atmospheric neutrinos (green) vs. source spectra with
- different spectral index (no cut-off)
- index = 2 and cut-off at
1 and 5 PeV.
normalized to dN/dE (1 TeV) = 10-11 TeV-1 cm-2 s-1
Aharonian, Gabici etc al. 2007
atmospheric neutrinos (green) vs. source spectra with
- different spectral index (no cut-off)
- index = 2 and cut-off at
1 and 5 PeV.
normalized to dN/dE (1 TeV) = 10-11 TeV-1 cm-2 s-1
What about the low energies when
increasing the spacing?
• Instrumenting a full cubic kilometer with small spacing is not
efficient since for low fluxes a further increase of the low energy
area will yield low-energy signal rates which are much lower
than the atmospheric neutrino background rates.
• Better: a small nested array with small spacing – enough
„exhaust“ the potential at low energy.
to
• Don‘t distribute the small spacing areas over the full array but
concentrate it in the center
–
–
–
–
Better shielding
No empty regions
Better performance for contained events
…
• DeepCore!
IceCube with DeepCore
IceCube with DeepCore
VETO
low-energy
nested array
Early IceCube
Exercises
12 clusters of strings
NT1000: top view
L~ 350
m
The present Baikal scenario
Compare to KM3NeT scenarios:
a
c
b
d
Content
• Lessons from IceCube
•
•
•
•
„Multi-wavelength“ point source searches
Network of Target of Opportunity projects
Other coordinated efforts
Cooperation on software and algorithms
• Formal questions
If n telescopes would be only sensitive
up to horizon ….
IceCube
„blind“
Antares
Baikal
KM3NeT
„blind“
… resulting in:
point source limits/sensitivities
Overlap region 25%
at any given moment,
70% of IceCube sky
seen by KM3NeT at
some moment.
Actually you can look above horizon
for higher energies:
+15°
+75°
+60°
+45°
24h
0h
+30°
+15°
24h
0h
-15°
-30°
-45°
R. Lauer, Heidelberg Workshop, Jan09
arXiv:0903.5434
IceCube 22 strings, 2007
Actually you can look above horizon
for higher energies:
+15°
+75°
+60°
+45°
24h
0h
+30°
+15°
24h
0h
-15°
-30°
-45°
IceCube 22 strings, 2007
Actually you can look above horizon
for higher energies:
IceCube 40 strings
6 months 2008
Differential IceCube sensitivity to point sources
(IC-40, 1 year, 5 discovery potential, normalized to ½ decade)
Taken from Chad Finley, MANTS
 = +30°
 = +60°
 = +6°
TeV
PeV
Differential IceCube sensitivity to point sources
(IC-40, 1 year, 5 discovery potential, normalized to ½ decade)
Taken from Chad Finley, MANTS
 = +30°
 = -8°
 = -30°  = -60°
 = +60°
 = +6°
TeV
PeV
Spectral form for extra-galactic sources
Multi-wavelength analysis of individual sources ?
 = +30°
 = -8°
 = -30°  = -60°
 = +60°
 = +6°
Blazars Stecker 2005
GRB-precursor
Razzaque 2008
3
TeV
4
WB prompt GRB
5
6
PeV
7
BLacs
Mücke et al
2003
8
9
Compare to absolute predictions
Taken from Chad Finley, MANTS
 = +30°
 = -8°
 = -30°  = -60°
 = +60°
Crab =+22°
MGRO J1908 =+6°
 = +6°
3C279 =-6°
• Predicted neutrino fluxes for a few selected sources (full lines)
• IC40 approximate 90% CL sensitivity to sources according to
flux model and declination (dashed lines)
Multi-wavelength/full sky analysis
• Cover 4p with 2 detectors  full sky map
• Add evidences/limits in overlap regions
• Combine TeV-PeV information from lower hemisphere
of one detector with PeV-EeV information from upper
hemisphere of the other detector
 multiwavelength analysis over 3-5 orders of
magnitude in wavelength / energy.
• Need:
–
–
–
–
Coordinated unblinding procedures
Coordinated candidate source list (also for source stacking)
Point spread functions
Effective areas as function of energy
Alert Programs
• GRB information from satellites
– offline analysis, online: storage of unfiltered data & high efficiency
at low E (like Antares)
• Optical follow-up:
n telescopes  robotic optical telescopes
• Gamma follow-up (NToO):
n telescopes  Gamma telescopes
• Supernova burst alert: IceCube (also KM3NeT? )
• Arguably, the ratio of signal to background alerts from n
telescopes is an issue. Alert programs have to be
coordinated worldwide, be it only not to swamp
optical/gamma telescopes with an unreasonable number
of alerts.
Optical Follow-Up
Antares Optical follow-up
„Neutrino Target of Opportunity“
Alert Programs
• GRB information from satellites
– offline analysis, online: storage of unfiltered data & high efficiency
at low E (like Antares)
• Optical follow-up:
n telescopes  robotic optical telescopes
• Gamma follow-up (NToO):
n telescopes  Gamma telescopes
• Supernova alert (IceCube)
• IceCube triggers KM3NeT and vice versa ?
Test: Antares  IceCube
Presentation of WIMP results
 Classes of tested models
 Presentation of model parameter space
 Comparison with direct searches
Other examples
 GRB stacking
 Combine KM3NeT/IceCube GRB lists, increasing the
overall sensitivity
 Diffuse fluxes
Any
- high energy excess (extraterrestrial or prompt n)
- high energy deficit (QG oscillations)
should be confirmed by an independent detector, with
different systematics
 Confirmation of exotic events
 Slowly moving particles (GUT monopoles, Q-balls,
nuclearites)  artefacts or reality?
Software and algorithms
MoU between IceCube and KM3NeT summer 2008
Framework:
IceTray  KM3Tray  SeaTray (now official software framework
for ANTARES and KM3NeT)
Improvements, debugging
KM3NeT  IceCube
Modules (future):
KM3NeT  IceCube
Simulation (event generators, air showers,…)
Reconstruction methods
Use of waveforms
Basic algorithms (like - already now – Gulliver fitting)
Content
• Lessons from IceCube
•
•
•
•
„Multi-wavelength“ point source searches
Network of Target of Opportunity projects
Other coordinated efforts
Cooperation on software and algorithms
• Formal questions
Formal framework
 Memoranda of Understanding on specific items
 like that on IceTray
 Yearly common meetings
 Similar to the one we had in Berlin (MANTS)
 Inter-collaboration working groups which
 „synchronize“ statistical methods, ways of presentation,
simulations, …
(for point sources, diffuse fluxes, dark matter, …)
 Global Network ?
 Like LIGO/Virgo/GEO
 Global Neutrino Observatory, with inter-collaboration
committees ?
 like Auger, CTA
Formal framework
 Memoranda of Understanding on specific items
 like that on IceTray
 Yearly common meetings
 Similar to the one we had in Berlin (MANTS)
 Inter-collaboration working groups which
 „synchronize“ statistical methods, ways of presentation,
simulations, …
 for point sources, diffuse fluxes, dark matter
 Global Network ?
 Like LIGO/Virgo/GEO
Could
start
this
with
the
full
community
 Global Neutrino Observatory, with inter-collaboration
Antares/KM3NeT, Baikal)
committees(IceCube,
?
 like Auger, CTA
A global network ?
But first of all ….
… let IceCube* try to do the best it can do for
KM3NeT:
…see a first source !
* and ANTARES. Who knows ?
Acknowledement
Part of this talk is based on talks given at the
MANTS Meeting, September 2009, in Berlin.
Special thanks to:
 Teresa Montaruli
 Jürgen Brunner
 Chad Finley
 Tom Gaisser, Uli Katz, Francis Halzen