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JUNO Workshop, IHEP, 2015/7/10 Active Galactic Nuclei & High Energy Neutrino Astronomy >TeV 黎卓 北京大学 Outline • • • • • Background: neutrino detection; sources AGN phenomena AGN neutrino models constraint by gamma-ray Conclusion HE neutrino flux implied by UHE cosmic ray • Neutrinos from production p ( p) N CR spectrum e e • If all p energy converted to j 1 1 1 / H 0 j p 2 2 GZK / c • Waxman-Bahcall Bound from detected >1019eV CR flux : dj GeV 8 10 d cm 2s sr 2 Waxman & Bahcall 1999 IceCube: KM scale •KM3 size to detect GZK neutrino, as well as SNR, AGN & GRB •DUMAND, 1976-1995 •AMANDA, operation 2000 •IceCube, completed 2010 10s evts/yr for WB bound High energy neutrino discovery 2010/5-2012/5 data: 1. EeV GZK neutrino search • found two at 1 PeV 2. Follow-up search: 28 evts 1. Lower E 2. Interaction vertices within detector volume Veto entering tracks North HE tracks? 3yr IC86, 37 evts, 5.7sigma (8.4 atm muon, 6.6 atm neutrino) South 30TeV-2PeV E-2 PL, 1:1:1, isotropic Diffuse neutrinos per flavor Harder than atmospheric events Uncertainty: charm meson decay Consistent with isotropic Disfavor charm component –which expect south 50% smaller than north Diffuse neutrinos Sky map, no significant spot Also no clustering in time, no correlation with GRB Spectrum: best fit E-2.3 Or E-2 spectrum + PeV cutoff •unbroken unlikely PeV neutrino source? • Galactic origin – CR propagation: diffuse – point sources (isotropic?!) • Pulsar, SNR, PWN, micro-quasar, … • Extragalactic origin – p-p: CR propagation • Star forming/starburst galaxies • Galaxy clusters • … – p-: in-source • Gamma ray bursts • Active galactic nuclei: jets & core • … Stacking search ~200 GRBs upper limit Null results… Gamma – neutrino connection p ( p) N e e e cascade radiation N 0 0 e synch/inve rse Comp radiation Connection: I. neutrino -- secondary electron II. neutrino -- secondary gamma-ray III. neutrino -- primary proton/electron Fermi-LAT probes neutrino origin Whether various candidates can produce the IceCube neutrino flux? Galactic diffuse emission: unlikely • Pi0 gamma-neutrino Fermi-LAT • Extrapolation: GeV to PeV – Galactic CR spectral index -2.75 – p-p neutrino spectrum follows CR IC MW diff. emis. [Wang, LZ, Zhao 2014] AGN property • Compact and strong nuclear emission – luminosity 10^43-48 erg/s; size <0.1pc (1pc=3.08E18cm) • Broad band radiation spectra FSRQ – primarily non-thermal, F∝-α (polarized) – thermal in some bands (but not from stars) • Strong emission lines – Widths suggest velocity up to 1E4 km/s • Variability BL Lac – in continuum and emission line flux, as well as line profile and polarization • Stronger X- and Gamma-ray (than normal galaxies) Unified model • BH • • • • • • – 1E6~1E10 Msun Disk Torus Jet BLR NLR … • Viewing angle effect Blazar spectrum: two bumps • Low energy bump – Electron synchrotron • Gamma origin – Leptonic model • electron IC – Hadronic model • Pi decay • P-synchrtron BL Lac 3C 66A AGN CRneutrino • Jet model – CR accelerated at Jet – Target photon: jet+disk+BLR+torus – Relativistic beaming; bright • Core model – CR accelerated at core region: disk or near BH – Target: disk photon – Isotropic emission; high pion production efficiency Dust torus (IR) Accretion disk (UV, X) CR CR Broad line region (optical, UV) Model uncertainty • L~LCR*f(n,r…) • Assumption: – Murase+14 (jet model) LCR=xCRLrad; ;need xCR>100-1000 – Stecker 91,92,05,13 (core model) L=Lx, 10%LMeV, … Blazars in IC neutrino fields • Blazars in the error box of IC’s neutrinos (three 0.1-1PeV neutrinos): [TANAMI, Krauß et al. 2014] – six resolved + unresolved • can produce IC’s neutrinos – assuming !! • ANTARES does not see neutrinos in those fields [ANTARES+TNAMI 2015] Integration Gamma – neutrino connection p ( p) N e e e cascade radiation N 0 0 e synch/inve rse Comp radiation Connection: I. neutrino -- secondary electron II. neutrino -- secondary gamma-ray III. neutrino -- primary proton/electron Flat spectrum radio quasar (FSRQ) jets • Assume – neutrino flux proportional to gamma flux – FSRQs can account for IC neutrinos Diffuse gamma-ray from FSRQs derived from Fermi-LAT survey Gamma>>neutrino flux • Neutrino/gamma flux ratio – (20TeV-2PeV)/(0.1100GeV)=3.8% • gamma (>0.1GeV) is not from hadronic model with cascade emission – where the flux ratio=O(1) – (p-synch still OK) [Wang & LZ 15] gamma neutrino [Fermi-LAT, Ajello+ 2012] Candidate FSRQs • apply the ratio to individual FSRQs • predict neutrino flux • comparison with IC limit • several sources in northern sky overpredicted [Wang & LZ, 2015] Stacking search • 33 bright FSRQs – selected based on gamma flux sensitivity • Prediction/limit>10 – >30 @ northern sky • So FSRQs can only account for <10% (<3%) IC neutrinos prediction upper limit [Wang & LZ, 2015] Conclusion & discussion • IceCube neutrino origin – Fermi-LAT observations disfavor • disfavor Galactic origin (diffuse emission & point sources), GRB, & AGN (FSRQ & BL Lac) jet • favor star forming/starburst galaxies – Current stacking limit cannot constrain AGN core model yet • Stack more AGN (how many?) • AGN jet still possible to be UHE CR sources – AGN neutrinos is a few% diffuse neutrinos; and f~a few%, – CR power maybe consistent with observed UHECR flux Starburst galaxies: II Fermi-LAT, Ackermann+12 Starburst galaxies: II • Local-universe gamma-ray emissivity • Redshift-integrated gamma-ray intensity • Neutrino flux and spectrum: – if CRs injected with ~Ep-2.2 as observed in MW – if <100PeV CRs lose energy significantly as expected in SBs Match both flux and spectrum by IC IC flux = WB bound? • Simply coincident? • The same sources for both >1019eV CR and IceCube neutrinos? – GRBs in starbursts Wang, Zhao & Li, 2014