connections icecube – km3net

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



Point sources (E-2)1 cubic kilometer IceCube



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

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




If telescopes would be only sensitive up to horizon ….

„blind“

„blind“

IceCube

AntaresBaikal

KM3NeT

… 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°

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+45°

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+75°

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-30°

-45°

-log

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R. Lauer, Heidelberg Workshop, Jan09 arXiv:0903.5434

IceCube 22 strings, 2007


0h24h

+15°

0h24h

+30°

+15°

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+60°

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IceCube 22 strings, 2007


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)


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°


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




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

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