PeV Neutrinos from Star-forming Regions Hajime Takami KEK, JSPS Fellow
Outline 0. Basic requirements for PeV neutrinos. Review on cosmogenic neutrinos for the PeV neutrinos. PeV neutrinos from Star-forming Regions
, Σp Required energy of cosmic rays and targets π p, π p K p, K p, Σp Total cross section (mb) - - - - - - Σp γp 0.- 0.0 - - -0. 0. π p, π p γ γ K p, K p γp 0.-.6 s= 0.0 - -0. γγ mp.6 πp.6 0..6 Reπ(T)p E p E 8 Im (T) 0.05 PeV.6.6 -.9 ev 5 6 7.6 K p total p 6 Ep 0.05 elastic E PeV ev Plab (GeV/c) - 5 6 7.6 8 ~ PeV protons ( ~ ev photons for pγ ) π p -0. E p Ep K p K p s GeV.6 πp 0.0-0. 0. -0. Plab (GeV/c) µ) sres Ep E ( elastic E p Ep π p E p 6 Re (T) K p ev Ep Im (T) PeV π0.05 p K p cm total Particle Data Group γγ 6 K p Re (T) Im (T) -0. 0. - cm sres.6 GeV 8 5 Total cross section (mb) p, interaction π p, π p γp K p, K p Cross section (mb) Total cross section (mb) pγ interaction Cross section (mb) 8
Link with the total cosmic-ray flux E ( PeV) = fe CR( PeV) E CR( PeV) 5 GeV cm s sr E ( PeV) 8 GeV cm s sr f = f p f ex pγ interaction p = n p ct interaction = n p ct t n cm fp fex 0. yr t 5 n p cm fp fex 0. yr
Propagation of UHECRs Photopion production CMB / IRB Bethe-Heitler Pair Creation GMF IGMF CMB / IRB Photodisintegration
Cosmogenic Neutrinos pectra of cosmogenic neutrinos with E min ¼ 6 (black) 7 (red) and 8 ev (blue) in the proton-dip scenario (left) and the ankle-transition scenario (right). The es, dotted lines, and dot-dashed lines show the spectra of m l þ m l ; m e þ m e, and m e from neutron beta decay, respectively. The cosmological evolution of UHECR sources trino oscillation are not taken into account. All fluxes are normalized by the Akeno AGASA spectrum. (For interpretation of the references to colour in this figure the reader is referred to the web version of this article.) IC 0 E dn/de [ev cm - ] 0 - - - - CMB Kneiske0 BEST Kneiske0 LIR Kneiske0 UV Stecker06 Fast Stecker 06 Fast x 0.6 EBL -5-5 - - - - 0 E [ev] HT et al., 009, Astropart. Phys.,, 0 redicted spectra of cosmogenic neutrinos per flavor ðm i þ m i Þ in the proton-dip scenario (solid lines) and ankle-transition scenario (dotted lines). These fluxes are zed by using the Akeno AGASA spectrum. E min and E max are set to 6 and ev. The red lines, green lines, and blue lines are neutrino spectra for the UNF, SFR, and BMAC source-evolution models, respectively. The fluxes of the atmospheric neutrinos (Atm m vertical/horizontal) [50] are represented. As uer limits of neutrino y several experiments, AMANDA-II limits [5,5], limit on tau neutrinos by the PAO [5], ANITA-lite limit [5] are shown. As estimated or projected sensitivities, ity of years observation by IceCube [55], sensitivity of 5 years observation by the PAO [56], ARIANNA sensitivity [57], and full-anita sensitivity [5] are also shown. se neutrino spectra from energetic sources, a maximal neutrino flux from active galactic nuclei including neutrino oscillation [58] and neutrino spectrum from GRBs ed in Ref. [59], considering neutrino oscillation, with their parameters of E jet ¼ : 5 erg, E sh ¼ 5 erg, n B ¼, n acc ¼ 0, C ¼ :5, r ¼ :5 cm and ¼ :5 cm, which are used in Ref. [60], are shown. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this The flux of cosmogenic neutrinos reaches ~ -9 GeV cm - s - sr -, which is one order of magnitude smaller than the IceCube flux in the cases of proton composition at the highest energies.
Each Component Proton dip (p =.7) Ankle transision (p =.0) H. Takami et al. / Astroparticle Physics (009) 0 07 π/μ decay n β-decay HT et al., 009, Astropart. Phys.,, 0 Fig.. Spectra of cosmogenic neutrinos with E min ¼ 6 (black) 7 (red) and 8 ev (blue) in the proton-dip scenario (left) and the ankle-transition scenario (right). The solid lines, dotted lines, and dot-dashed lines show the spectra of m l þ m l ; m e þ m e, and m e from neutron beta decay, respectively. The cosmological evolution of UHECR sources and neutrino oscillation are not taken into account. All fluxes are normalized by the Akeno AGASA spectrum. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
Heavy Nuclei Case Fe sources, α=.0, E max =500 EeV, GRB -6-7 Auger spectrum Hires spectrum XGal CRs neutrinos anti-ν e (n decay) IC0 Auger Anita E dφ/de [GeV/cm s sr] -8-9 - IC - - 5 6 7 8 9 0 E [ev] Roulet et al., 0, JCAP, 0, 08 The flux of cosmogenic neutrinos from heavy nuclei is far from the IceCube flux level.
Extragalactic Contribution to lower-energy CRs Give up to connect it to the highest energy cosmic rays! je, ev cm - s - sr - 7 6 5 0 p γν Stecker-Malkan-Scully (006) model Relatively high optical/uv photon density Almost ruled out from recent Fermi data. - 6 8 E, ev Kalashev, Kusenko, Essey 0, PRL,, 0 lcr ~ 9 - erg Mpc - s - - (nagn ~ -5 Mpc - ) -> LCR = - 6 erg s -
Short Summary on the Cosmogenic Interpretations If the highest energy cosmic rays produce cosmogenic neutrinos, cosmogenic neutrinos are difficult to reproduce the IceCube flux. Their flux reaches only ~ -9 GeV cm - s - sr - in the pure proton composition, their flux is only <~ - GeV cm - s - sr - in the Fe composition, and neutrinos from neutron decay are negligible. If cosmic rays up to the second knee are extragalactic protons, the IceCube flux could be explained, but this scenario requires (almost ruled-out) high-density EBL models, proton domination beyond the knee, and (if AGN) cosmic-ray luminosity comparable with or higher than the Eddington luminosity.
Summary Cosmogenic neutrinos related to the highest energy cosmic rays are difficult to reproduce the IceCube flux. Cosmogenic neutrinos related to the second knee region could realize the IceCube flux, but strong assumptions are required. Star-forming galaxies could be a good candidate of PeV neutrinos.