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

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

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 1016 - 1018 eV Form of spectrum requires Galactic accelerators up to 3 PeV (PeVatrons) Not identifiable with cosmic ray experiments (magnetic fields) galactic extragalactic April 23, 2008 Alexander Kappes, 3rd VLVnT Workshop, Toulon France

The Cosmic-Ray Gamma/Neutrino Connection p + p() → p + X 9 m + nm 9 e + ne + nm p + p() → p0 + X 9   Hadronic neutrino and -ray production: ( ne : nm : nt )  (  :  : 0 Relation  /  spectrum parameters (at Earth   mixing leads to (1 : 1 : 1)) Protons @ CR “knee” produce -rays of ~300 TeV Norm: Index: Cut-off: Kappes etal: ApJ,656:870-896,2007 April 23, 2008 Alexander Kappes, 3rd VLVnT Workshop, Toulon France

The Mystery of the Missing PeVatrons 400 yr 2000 yr 8000 yr 32000 yr (104 solar masses) at 1 Kpc Cherenkov telescopes (e.g. HESS, Magic) Air shower arrays (Milagro) Gabici, Aharonian: arXiv:0705.3011 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 April 23, 2008 Alexander Kappes, 3rd VLVnT Workshop, Toulon France

2007 Milagro Sky Survey At 12 TeV Abdo thesis defense, March 2007 TeV J2032+4130 MAGIC: arXiv:0801.2391 F = (4.5 ± 0.3) × 10-13 E-2.0±0.3 (TeV-1 cm-2 s-1) VERITAS observation 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 April 23, 2008 Alexander Kappes, 3rd VLVnT Workshop, Toulon France

Gamma-ray Spectrum of MGRO J1908+06 preliminary 60 90 Revised H.E.S.S. flux now factor 2 lower ! Sabrina Casanova @ Heidelberg workshop, Jan 2008 E (TeV) Again E-2 spectrum; extends up to 100 TeV ! Strong indicator of proton acceleration in this source April 23, 2008 Alexander Kappes, 3rd VLVnT Workshop, Toulon France

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 deg2) 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) April 23, 2008 Alexander Kappes, 3rd VLVnT Workshop, Toulon France

Gamma and Neutrino Spectra Spectra for MGRO J1908+06 Neutrino spectra for all sources MGRO J1852+01 MGRO J2019+37 MGRO J1908+06 MGRO J2031+41 MGRO J2043+36 MGRO J2032+37 10-11 10-10 E2flux (TeV s-1 cm-2) E2flux (TeV s-1 cm-2) 10-11 gamma flux 10-12 10-12 neutrino flux 10-13 10-13 1 10 100 1000 1 10 100 1000 Ethresh (TeV) Ethresh (TeV) Halzen, Kappes, O’Murchadha: arXiv:0803.0314 Assumed E-2 with Milagro normaliztion (MGRO J1908+06 index = 2.1) spectrum cutoff @ 180 TeV April 23, 2008 Alexander Kappes, 3rd VLVnT Workshop, Toulon France

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

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

Simulated Neutrino Skymaps IC80 (5 years) # events (arb. units) Correlated Skymap April 23, 2008 Alexander Kappes, 3rd VLVnT Workshop, Toulon France

Alexander Kappes, 3rd VLVnT Workshop, Toulon France 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 after several years (best sensitivity above several 10 TeV) MGRO J1852+01 and MGRO J1908+06 also visible (50%) by Mediterranean detectors April 23, 2008 Alexander Kappes, 3rd VLVnT Workshop, Toulon France