649 research outputs found

    An hourglass model for the flare of HST-1 in M87

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    To explain the multi-wavelength light curves (from radio to X-ray) of HST-1 in the M87 jet, we propose an hourglass model that is a modified two-zone system of Tavecchio & Ghisellini (hereafter TG08): a slow hourglass-shaped or Laval nozzle-shaped layer connected by two revolving exponential surfaces surrounding a fast spine, through which plasma blobs flow. Based on the conservation of magnetic flux, the magnetic field changes along the axis of the hourglass. We adopt the result of TG08---the high-energy emission from GeV to TeV can be produced through inverse Compton by the two-zone system, and the photons from radio to X-ray are mainly radiated by the fast inner zone system. Here, we only discuss the light curves of the fast inner blob from radio to X-ray. When a compressible blob travels down the axis of the first bulb in the hourglass, because of magnetic flux conservation, its cross section experiences an adiabatic compression process, which results in particle acceleration and the brightening of HST-1. When the blob moves into the second bulb of the hourglass, because of magnetic flux conservation, the dimming of the knot occurs along with an adiabatic expansion of its cross section. A similar broken exponential function could fit the TeV peaks in M87, which may imply a correlation between the TeV flares of M87 and the light curves from radio to X-ray in HST-1. The Very Large Array (VLA) 22 GHz radio light curve of HST-1 verifies our prediction based on the model fit to the main peak of the VLA 15 GHz radio light curve.Comment: 14 pages, 2 figures, accepted for publication in A

    iParker-A New Smart Car-Parking System Based on Dynamic Resource Allocation and Pricing

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    Research on BOM Mapping transformation for Ship Construction Process

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    Abstract: Due to the problem about the core departmental "information isolated island" with BOM, various stages of ship product design section are convergence off and impeded the construction of agile ship the product. In this paper, first, establish the various stages of the ship product BOM structure model, based on a comparison of the structural model analysis, design a more practical conversion method, and then describe the conversion process about the ship product life cycle BOM view in order to quickly build a variety of BOM view. Keywords: BOM; BOM tectonic model; BOM view of conversio
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