40,673 research outputs found

    Broad-line and Multi-wave Band Emission from Blazars

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    We study the correlations of the flux of the broad-line emission (FBLRF_{BLR}) with the X-ray emission flux, optical emission flux at 5500 \AA and radio emission flux at 5 GHz, respectively, for a large sample of 50 Blazars (39 flat-spectrum radio quasars (FSRQs) and 11 BL Lac objects). Our main results are as follows. There are very strong correlations between FBLRF_{BLR} and FXF_{X} and between LBLRL_{BLR} and LXL_{X} in both states for 39 FSRQs and the slopes of the linear regression equations are almost equal to 1. There are weak correlations between FBLRF_{BLR} and FXF_{X} and between LBLRL_{BLR} and LXL_{X} for 11 BL Lac objects in both states, and the slopes of the linear regression equations are close to 1. There are significant correlations between FBLRF_{BLR} and FXF_{X} and between LBLRL_{BLR} and LXL_{X} for 50 blazars in both states, the slopes of both the linear regression equations are also close to 1. These results support a close link between relativistic jets and accretion on to the central Kerr black hole. On the other hand, we find that BL Lac objects have low accretion efficiency Ξ·\eta, whereas FSRQs have high accretion efficiency Ξ·\eta. The unified model of FSRQs and BL Lac objects is also discussed.Comment: 15 pages, 8 figure

    Effect of chain stiffness on ion distributions around a polyelectrolyte in multivalent salt solutions

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    Ion distributions in dilute polyelectrolyte solutions are studied by means of Langevin dynamics simulations. We show that the distributions depend on the conformation of a chain while the conformation is determined by the chain stiffness and the salt concentration. We observe that the monovalent counterions originally condensed on a chain can be replaced by the multivalent ones dissociated from the added salt due to strong electrostatic interaction. These newly condensed ions give an important impact on the chain structure. At low and at high salt concentrations, the conformation of a semiflexible chain is rodlike. The ion distributions show similarity to those for a rigid chain, but difference to those for a flexible chain whose conformation is a coil. In the mid-salt region, the flexible chain and the semiflexible chain collapse but the collapsed chain structures are, respectively, disordered and ordered structures. The ion distributions hence show different profiles for these three chain stiffness with the curves for the semiflexible chain lying between those for the flexible and the rigid chains. The number of the condensed multivalent counterions, as well as the effective chain charge, also shows similar behavior, demonstrating a direct connection with the chain morphology. Moreover, we find that the condensed multivalent counterions form triplets with two adjacent monomers and are localized on the chain axis at intermediate salt concentration when the chain stiffness is semiflexible or rigid. The microscopic information obtained here provides valuable insight to the phenomena of DNA condensation and is very useful for researchers to develop new models.Comment: 28 pages, 10 figures, accepted for publication in JC
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