893 research outputs found

    Rotation of Polarization Angle in Gamma-Ray Burst Prompt Phase-\uppercase\expandafter{\romannumeral2}. The Influence of The Parameters

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    In addition to the light curve and energy spectrum, polarization is also important for the study of Gamma-ray burst (GRB) prompt emission. Rotation of the polarization angle (PA) with time will cause depolarization of the time-integrated polarization degree. However, it is rarely studied before. Here, we use the magnetic reconnection model with a large-scale ordered aligned magnetic field in the emitting region to study the influence of the key parameters on the PA rotations. We find that half-opening angle of the jet θj\theta_{j}, the observational angle θV\theta_{V}, and the bulk Lorentz factor Γ\Gamma all have significant impacts on the PA rotations. For a fixed θjΓ0\theta_{j}\Gamma_{0} value (Γ0\Gamma_{0} is the normalization factor of Γ\Gamma), regardless of concrete θj\theta_{j} and Γ0\Gamma_{0} values, PA rotation within T90T_{90} (\trianglePA) remains roughly unchanged for a qθV/θjq\equiv\theta_{V}/\theta_{j} value. As θjΓ0\theta_{j}\Gamma_{0} value increases, the qq range for \trianglePA>10>10^{\circ} becomes smaller. The most significant PA rotation with \trianglePA90\thicksim90^{\circ} will happen when θjΓ0100\theta_{j}\Gamma_{0}\thicksim100 and 1.1q1.21.1\leq q\leq1.2. For the top-hat jet, observations of the PA rotation within T90T_{90} will imply a slightly off-axis observation.Comment: 9 pages, 7 figures, submitte

    A systematic study on the binding energy of Λ\Lambda hypernuclei

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    In this paper, we calculated the binding energy per baryon of the Λ\Lambda hypernuclei systemically, using the relativistic mean field theory (RMF) in a statistic frame. Some resemble properties are found among most of the hypernuclei found in experiments. The data show that a Λ\Lambda hypernucleus will be more stable, if it is composed of a Λ\Lambda hyperon adding to a stable normal nuclear core, or a Λ\Lambda hyperon replacing a neutron in a stable normal nuclear core. According to our calculations, existences of some new Λ\Lambda hypernuclei are predicted under the frame of RMF.Comment: 8 pages, 6 figures, 3 table

    On coincidence and common fixed point theorems of eight self-maps satisfying an FM-contraction condition

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    In this paper, a new type of contraction for several self-mappings of a metric space, called FM-contraction, is introduced. This extends the one presented for a single map by Wardowski [Fixed points of a new type of contractive mappings in complete metric spaces, Fixed Point Theory Appl., 2012:94, 2012]. Coincidence and common fixed point of eight self mappings satisfying FM-contraction conditions are established via common limit range property without exploiting the completeness of the space or the continuity of the involved maps. Coincidence and common fixed point of eight self-maps satisfying FM-contraction conditions via the common property (E.A.) are also studied. Our results generalize, extend and improve the analogous recent results in the literature, and some examples are presented to justify the validity of our main results