1. Prospects of Identifying the Sources of the Galactic Cosmic Rays with IceCube Alexander Kappes Francis Halzen Aongus O’Murchadha University Wisconsin-Madison 3 rd VLVnT Workshop April 22. - 24. 2008, Toulon France

2. April 23, 2008Alexander Kappes, 3rd VLVnT Workshop, Toulon France2 Outline  Cosmic rays and gamma/neutrino production  Which are the accelerators of the Galactic cosmic rays?  Can we see them with neutrino telescopes (IceCube)?

3. April 23, 2008Alexander Kappes, 3rd VLVnT Workshop, Toulon France3 The Cosmic Ray Spectrum  Cosmic ray spectrum measured over more than 12 decades  Spectrum steepens at ~3 PeV  Transition between Galactic and extra-Galactic component at 10 16 - 10 18 eV  Form of spectrum requires Galactic accelerators up to 3 PeV (PeVatrons)  Not identifiable with cosmic ray experiments (magnetic fields) extragalacticgalactic

4. April 23, 2008Alexander Kappes, 3rd VLVnT Workshop, Toulon France4 The Cosmic-Ray Gamma/Neutrino Connection  Relation  / spectrum parameters (pp interactions) (at Earth  mixing leads to (1 : 1 : 1))  Protons @ CR “knee” produce  -rays of ~300 TeV p + p(  ) →   + X   +   e + e +  p + p(  ) →  0 + X    Hadronic neutrino and  ray production: ( e :     Norm: Index: Cut-off: Kappes etal: ApJ,656:870-896,2007

5. April 23, 2008Alexander Kappes, 3rd VLVnT Workshop, Toulon France5 The Mystery of the Missing PeVatrons  SNRs best candidates for Galactic cosmic ray accelerators  But no SNR  spectrum extends above a few 10 TeV  Possible reason: “Direct” high energy  -ray emission only in first few hundred years  Detection still possible by observing secondary  -rays produced in nearby clouds  Milagro better suited than Cherenkov telescopes 400 yr 2000 yr 8000 yr 32000 yr (10 4 solar masses) at 1 Kpc 8000 yr 2000 yr Cherenkov telescopes (e.g. HESS, Magic) Air shower arrays (Milagro) Gabici, Aharonian: arXiv:0705.3011

6. April 23, 2008Alexander Kappes, 3rd VLVnT Workshop, Toulon France6 2007 Milagro Sky Survey At 12 TeV MGRO J2019+37 MGRO J2032+37 MGRO J2031+41 MGRO J1852+01 MGRO J1908+06 MGRO J2043+36  MGRO 2019+37: not seen by VERITAS in first observation  consistency requires  < 2.2  MGRO J2031+41: Magic measures E -2 spectrum Abdo thesis defense, March 2007 VERITAS observation

7. April 23, 2008Alexander Kappes, 3rd VLVnT Workshop, Toulon France7 Gamma-ray Spectrum of MGRO J1908+06  Again E -2 spectrum; extends up to 100 TeV !  Strong indicator of proton acceleration in this source

8. April 23, 2008Alexander Kappes, 3rd VLVnT Workshop, Toulon France8 The Role of Neutrino Telescopes  Air shower array currently only in Northern Hemisphere  Photon production ambiguous  Cherenkov telescopes have only small field of view (few deg 2 ) cover only small part of sky (at a time) large photon background in star forming region (e.g. Cygnus) can hide sources  Neutrinos unambiguous sign for hadronic acceleration  Neutrino telescope properties fit well to air shower arrays “all sky” sensitivity increasing sensitivity with energy (small background) angular resolution O (1º)

9. April 23, 2008Alexander Kappes, 3rd VLVnT Workshop, Toulon France9 Gamma and Neutrino Spectra Neutrino spectra for all sources Spectra for MGRO J1908+06  Assumed E -2 with Milagro normaliztion (MGRO J1908+06 index = 2.1)   spectrum cutoff @ 180 TeV Halzen, Kappes, O’Murchadha: arXiv:0803.0314 neutrino flux gamma flux MGRO J1852+01 MGRO J2019+37 MGRO J1908+06 MGRO J2031+41 MGRO J2043+36 MGRO J2032+37 1 10 E thresh (TeV) 1000 100 1 10 E thresh (TeV) 1000 100 10 -13 10 -12 10 -11 10 -10 E 2  flux (TeV s -1 cm -2 ) 10 -13 10 -12 10 -11

10. April 23, 2008Alexander Kappes, 3rd VLVnT Workshop, Toulon France10 Significance for MGRO J1908+06 (5 years) Milagro measurements favor lower sensitivity curve (dashed line)  2 - 2.5  after 5 years  IceCube (80 strings) effective area (with quality cuts)  Search window: observed events signal + atm. calculated signal events Halzen, Kappes, O’Murchadha: arXiv:0803.0314 11 22 33 1 10 E thresh (TeV) 100 1 10 E thresh (TeV) 100 1 10 # events p value

11. April 23, 2008Alexander Kappes, 3rd VLVnT Workshop, Toulon France11 Significance for all 6 Milagro sources after 5 years  p-value = 10 -4 after 5 years but large error band (not shown)  Optimal threshold @ 30 TeV (determined by loss of signal events) Halzen, Kappes, O’Murchadha: arXiv:0803.0314

12. April 23, 2008Alexander Kappes, 3rd VLVnT Workshop, Toulon France12 Simulated Neutrino Skymaps IC80 (5 years) # events (arb. units) Correlated Skymap Not actual way to analyse data !

13. April 23, 2008Alexander Kappes, 3rd VLVnT Workshop, Toulon France13 Summary  Cosmic ray sources (PeVatrons) should leave imprint on Milagro sky map  Milagro observes several hotspots with apparently hard spectra  maybe first PeVatron(s) discovered (MGRO J1908+06)  If these are the cosmic ray sources IceCube will be able to see them with time (best sensitivity above several 10 TeV)  MGRO J1852+01 and MGRO J1908+06 also visible (50%) by Mediterranean detectors More information in Halzen, Kappes, O’Murchadha: arXiv:0803.0314

14. April 23, 2008Alexander Kappes, 3rd VLVnT Workshop, Toulon France14 The TeV Gamma-Ray Sky