connections icecube – km3net
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
Connections IceCube – KM3NeT
Christian SpieringDESY
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:– 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.
IceCube: 125 m
E-2
Early IceCube spacing exercises
• Increasing the string spacing from 100 to 180 m improves:– 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
Too optimistic
Not important in water
IceCube: 125 m
Threshold for best sensitivity
Blue: after downgoing muon rejectionRed: after cut for ultimate sensitivity
Diffuse E-2 flux1 cubic kilometer IceCube
Threshold for best sensitivity
Blue: after downgoing muon rejectionRed: after cut for ultimate sensitivity
Point sources (E-2)1 cubic kilometer IceCube
Threshold for best sensitivity
Blue: after downgoing muon rejectionRed: after cut for ultimate sensitivity
Point sourcesSeveral cubic kilometers (educated guess)
Threshold between 3 and 5 TeV !
Ceterum censeo:
• Optimize to energies > 5 TeV, even if you have to sacrifice lower energies!
• See original GVD/Baikal with muon threshold ~ 10 TeV (but, alas, < 1 km³)
624m
280m
70m70m12
0m
208m
Expected flux from galactic point sources, example: RXJ 1713-3946 (see also Paolo Lipari’s talk)
Assume 0 and calculate related ±
C. Stegmann ICRC 2007
Milagro sources in Cygnus region
• 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)
Halzen, Kappes, O’Murchadha
Probability for fake detection:
Aharonian, Gabici etc al. 2007atmospheric 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. 2007atmospheric 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 to „exhaust“ the potential at low energy.
• 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-energynested array
Early IceCubeExercises
The present Baikal scenario
12 clusters of strings
NT1000: top view
R ~ 60 mL~
350
m
Compare to KM3NeT scenarios:a b
c 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 telescopes would be only sensitive up to horizon ….
„blind“
„blind“IceCube
AntaresBaikalKM3NeT
… resulting in:
Overlap region 25% at any given moment, 70% of IceCube sky seen by KM3NeT at some moment.
point source limits/sensitivities
Actually you can look above horizon for higher energies:
0h24h
+15°
0h24h
+30°
+15°
+45°
+60°+75°
-15°
-30°
-45°
-log 1
0 p
-log 1
0 p
R. Lauer, Heidelberg Workshop, Jan09 arXiv:0903.5434
IceCube 22 strings, 2007
Actually you can look above horizon for higher energies:
0h24h
+15°
0h24h
+30°
+15°
+45°
+60°+75°
-15°
-30°
-45°
-log 1
0 p
-log 1
0 p
IceCube 22 strings, 2007
Actually you can look above horizon for higher energies:
IceCube 40 strings6 months 2008
Differential IceCube sensitivity to point sources (IC-40, 1 year, 5 discovery potential, normalized to ½ decade)
= +6°
= +30°
= +60°
Taken from Chad Finley, MANTS
TeV PeV
= +6°
= +30°
= +60°
= -8° = -30° = -60°
Differential IceCube sensitivity to point sources (IC-40, 1 year, 5 discovery potential, normalized to ½ decade)
Taken from Chad Finley, MANTS
TeV PeV
= +30°
= +60°
= -8° = -30° = -60°
Spectral form for extra-galactic sources
= +6°
3 4 5 6 7 8 9
GRB-precursorRazzaque 2008 WB prompt GRB
Blazars Stecker 2005
BLacsMücke et al 2003
TeV PeV
Multi-wavelength analysis of individual sources ?
Compare to absolute predictions
• 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)
Crab =+22°
MGRO J1908 =+6°3C279 =-6°
= +6°
= +30°
= +60°
= -8° = -30° = -60°
Taken from Chad Finley, MANTS
Multi-wavelength/full sky analysis
• Cover 4 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: telescopes robotic optical telescopes
• Gamma follow-up (NToO): telescopes Gamma telescopes
• Supernova burst alert: IceCube (also KM3NeT? )
• Arguably, the ratio of signal to background alerts from 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: telescopes robotic optical telescopes
• Gamma follow-up (NToO): 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 fluxesAny
- high energy excess (extraterrestrial or prompt )- 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
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 methodsUse of waveformsBasic algorithms (like - already now – Gulliver fitting)
MoU between IceCube and KM3NeT summer 2008
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 Global Neutrino Observatory, with inter-collaboration
committees ? like Auger, CTA
Could start this with the full community (IceCube, Antares/KM3NeT, Baikal)
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