Physics of multiple level hairpin vortex structures in turbulence

Wang, Yi Qian; Al-Dujaly, Hassan Abd Salman; Yan, Yong Hua; Zhao, Ning; Liu, Chao Qun

doi:10.1007/s11433-015-5757-5

Cited by 20 publications

(12 citation statements)

References 24 publications

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“…1). The conclusion is consistent with the result by simply assuming constant ratio of neutrino to gamma-ray flux from blazars [15].…”

Section: Summary and Discussionsupporting

confidence: 90%

“…On the other hand, once L γ and E ν L Eν are measured, ξ cr can be determined or constrained. Note that unlike [15] which assumes simple proportionality of neutrino and gamma-ray luminosities, here L rad and f pγ are not strict linear function of L γ , so the neutrino luminosity E ν L Eν (eq. 2) is not strictly linear function of L γ either.…”

Section: Blazar Emissionmentioning

confidence: 99%

“…There are already many extragalactic objects proposed to produce CRs and neutrinos long before the IceCube detection [e.g., [9][10][11][12][13][14]. However, using the Fermi-LAT observations of those potential sources and simply assuming the gamma-ray to neutrino flux ratio is constant, [7,15] suggested that gamma-ray bursts and flat spectrum radio quasars (FSRQs) may not account for the IceCube neutrino flux, but starburst galaxies are still possible.…”

Section: Introductionmentioning

confidence: 99%

“…It is expected that the CRs produced by the jet interact with photons from or outside of the jet can produce pions and hence neutrinos. Many discussions are going on after the IceCube detection for whether blazars can account for the IceCube neutrinos [15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

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Constraints on cosmic ray and PeV neutrino production in blazars

Zhang

2017

J. Cosmol. Astropart. Phys.

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IceCube has detected a cumulative flux of PeV neutrinos, which origin is unknown. Blazars, active galactic nuclei with relativistic jets pointing to us, are long and widely expected to be one of the strong candidates of high energy neutrino sources. The neutrino production depends strongly on the cosmic ray power of blazar jets, which is largely unknown. The recent null results in stacking searches of neutrinos for several blazar samples by IceCube put upper limits on the neutrino fluxes from these blazars. Here we compute the cosmic ray power and PeV neutrino flux of Fermi-LAT blazars, and find that the upper limits for known blazar sources give stringent constraint on the cosmic ray loading factor of blazar jets (i.e., the ratio of the cosmic ray to bolometric radiation luminosity of blazar jets), ξcr < ∼ (2 − 10)ζ −1 (with ζ < ∼ 1 the remained fraction of cosmic ray energy when propagate into the blazar broad line region) for flat cosmic ray spectrum, and that the cumulative PeV neutrino flux contributed by all-sky blazars is a fraction < ∼ (10 − 50)% of the IceCube detected flux.

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“…1). The conclusion is consistent with the result by simply assuming constant ratio of neutrino to gamma-ray flux from blazars [15].…”

Section: Summary and Discussionsupporting

confidence: 90%

Section: Blazar Emissionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Constraints on cosmic ray and PeV neutrino production in blazars

Zhang

2017

J. Cosmol. Astropart. Phys.

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“…The potential astrophysical sources to produce high-energy neutrinos and photons include star-forming galaxies (Loeb & Waxman 2006;He et al 2013;Anchordoqui et al 2014;Liu et al 2014;Tamborra et al 2014;Wang et al 2014;Chang et al 2015), tidal disruption events , gamma-ray bursts (GRBs) (Waxman & Bahcall 1997;Cholis & Hooper 2013;Murase & Ioka 2013), active galactic nucleus (AGNs) (Anchordoqui et al 2008;Kalashev et al 2013;Stecker 2013;Murase et al 2014;Dermer et al 2014), double white dwarf mergers (Xiao et al 2016) and even Galactic sources (Fox et al 2013;Razzaque 2013;Ahlers & Murase 2014;Lunardini et al 2014;Neronov et al 2014), see Ahlers & Halzen (2015) for a review. However, combined data analysis between IceCube neutrinos events and γ-ray sources sample, such as GRBs, AGNs, soft γ-ray repeaters, supernova remnants, pulsars, microquasars, and X-ray binaries (Padovani & Resconi 2014;Krauß et al 2014;Aartsen et al 2015a,b;Padovani et al 2016;Glüsenkamp 2016;Aartsen et al 2016;Wang & Li 2016), do not reveal any firm associations up to now.…”

Section: Introductionmentioning

confidence: 93%

Search for GeV and X-Ray Flares Associated with the IceCube Track-like Neutrinos

Peng

Wang

2017

ApJ

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Dozens of high-energy neutrinos have been detected by the IceCube neutrino telescope, but no clear association with any classes of astrophysical sources has been identified so far. Recently, Kadler et al. (2016) report that a PeV cascade-like neutrino event occurs in positional and temporal coincidence with a giant gamma-ray flare of the blazar PKS B1424-418. Since IceCube track-like events have much better angular resolution, we here search for possible shortterm gamma-ray flares that are associated with the IceCube track-like events with Fermi Large Area Telescope (LAT) observations. Among them, three track-like neutrino events occur within the field of view of Fermi-LAT at the time of the detection, so search for the prompt gamma-ray emission associated with neutrinos are possible. Assuming a point source origin and a single power law spectrum for the possible gamma-ray sources associated with neutrinos, a likelihood analysis of 0.2-100 GeV photons observed by Fermi-LAT on the timescales of ∼ 12 hours and one year are performed, and for the three special neutrinos, the analysis are also performed on the timescales of thousand of seconds before and after the neutrino detection. No significant GeV excesses over the background are found and the upper limit fluxes at 95% confidence level are obtained for different timescales. We also search for possible hard X-ray transient sources associated with the IceCube track-like neutrino events, but the search also yields null results. We discuss the implication of the non-detection of gamma-ray flares for the constraints on the neutrino source density.

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New theory on turbulence generation and structure—DNS and experiment

Liu

Cai

2017

Sci. China Phys. Mech. Astron.

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Physics of multiple level hairpin vortex structures in turbulence

Cited by 20 publications

References 24 publications

Constraints on cosmic ray and PeV neutrino production in blazars

Constraints on cosmic ray and PeV neutrino production in blazars

Search for GeV and X-Ray Flares Associated with the IceCube Track-like Neutrinos

New theory on turbulence generation and structure—DNS and experiment

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