Jet-cloud/star interaction as an interpretation of neutrino outburst from the blazar TXS 0506+056

Recently, a high-energy neutrino event IceCube-170922A in the spatial and temporal coincidence with the flaring gamma-ray blazar TXS 0506+056 was reported. A neutrino outburst between September 2014 and March 2015 was discovered in the same direction by a further investigation of $9.5$ years of IceCube data, while the blazar is in a quiescent state during the outburst with a gamma-ray flux only about one-fifth of the neutrino flux. In this letter, we propose the neutrino outburst originates from the interaction between a relativistic jet and a dense gas cloud which may be formed via the tidally disrupted envelope of a red giant being blown by the impact of the jet. Gamma-ray photons and electron/positron pairs that are produced correspondingly will induce electromagnetic cascades. Comptonization of the cascade emission inside the cloud forms an X-ray photon field with Wien distribution. GeV flux is suppressed due to the absorption by the Comptonized photon field and, as a result, a hard spectrum above 10 GeV is formed. The gamma-ray spectrum predicted in our model is consistent with the Fermi-LAT data of TXS 0506+056.Comment: 6 pages, 3 figure

IceCube Non-detection of GRBs: Constraints on the Fireball Properties

The increasingly deep limit on the neutrino emission from gamma-ray bursts (GRBs) with IceCube observations has reached the level that could put useful constraints on the fireball properties. We first present a revised analytic calculation of the neutrino flux, which predicts a flux an order of magnitude lower than that obtained by the IceCube collaboration. For benchmark model parameters (e.g. the bulk Lorentz factor is \Gamma=10^{2.5}, the observed variability time for long GRBs is t_v=0.01 s and the ratio between the energy in accelerated protons and in radiation is \eta_p=10 for every burst) in the standard internal shock scenario, the predicted neutrino flux from 215 bursts during the period of the 40-string and 59-string configurations is found to be a factor of ~3 below the IceCube sensitivity. However, if we accept the recently found inherent relation between the bulk Lorentz factor and burst energy, the expected neutrino flux increases significantly and the spectral peak shifts to lower energy. In this case, the non-detection then implies that the baryon loading ratio should be \eta_p<10 if the variability time of long GRBs is fixed to t_v=0.01 s. Instead, if we relax the standard internal shock scenario but keep to assume \eta_p=10, the non-detection constrains the dissipation radius to be R>4x10^{12} cm assuming the same dissipation radius for every burst and benchmark parameters for fireballs. We also calculate the diffuse neutrino flux from GRBs for different luminosity functions existing in the literature. The expected flux exceeds the current IceCube limit for some luminosity functions, and thus the non-detection constrains \eta_p<10 in such cases when the variability time of long GRBs is fixed to t_v=0.01 s.Comment: Accepted by ApJ, 14 pages, 5 figures, typos corrected, scheduled for the June 10, 2012, v752 - 1 issu

Modeling and Analysis of Bifurcation in a Delayed Worm Propagation Model

A delayed worm propagation model with birth and death rates is formulated. The stability of the positive equilibrium is studied. Through theoretical analysis, a critical value τ0 of Hopf bifurcation is derived. The worm propagation system is locally asymptotically stable when time delay is less than τ0. However, Hopf bifurcation appears when time delay τ passes the threshold τ0, which means that the worm propagation system is unstable and out of control. Consequently, time delay should be adjusted to be less than τ0 to ensure the stability of the system stable and better prediction of the scale and speed of Internet worm spreading. Finally, numerical and simulation experiments are presented to simulate the system, which fully support our analysis

Research of Variable Volume and Gas Injection DC Inverter Air Conditioning Compressor

With the wide promotion of energy saving and environmental protection, the improvement of heating capacity especially at low ambient temperature condition and the working efficiency of room air conditioner become more and more important. Firstly, the purpose of this paper was introduced. Then, the relative techniques like DC inverter, variable volume and gas injection were simply analyzed. Thirdly, a new coupling compressor with these three techniques to satisfy both heating capacity and efficiency demands was indicated. Moreover, the detail design of the coupling compressor was described. At last, the prototype compressor was designed and assembled to validate the effect of this coupling compressor on RAC system. According to the test result, this coupling compressor has significant effect as we expectation when using in RAC system. The maximum heating capacity increasing up to 185% by compare to the base system at -15℃ ambient temperature condition which makes half time consumption at the same room temperature rising. Furthermore, the APF efficiency of the system increased by about 6%

Categorizing resonances X(1835), X(2120) and X(2370) in the pseudoscalar meson family

Inspired by the newly observed three resonances X(1835), X(2120) and X(2370), in this work we systematically study the two-body strong decays and double pion decays of $\eta(1295)/\eta(1475)$, $\eta(1760)/X(1835)$ and $X(2120)/X(2370)$ by categorizing $\eta(1295)/\eta(1475)$, $\eta(1760)/X(1835)$, X(2120) and X(2370) as the radial excitations of $\eta(548)/\eta^\prime(958)$. Our numerical results indicate the followings: (1) The obtained theoretical strong decay widths of three pseudoscalar states $\eta(1295)$, $\eta(1475)$ and $\eta(1760)$ are consistent with the experimental measurements; (2) X(1835) could be the second radial excitation of $\eta^\prime(958)$; (3) X(2120) and X(2370) can be explained as the third and fourth radial excitations of $\eta(548)/\eta^\prime(958)$, respectively.Comment: 16 pages, 15 figures, 3 tables. Accepted for publication in Phys. Rev.