3,286 research outputs found

    DD-dimensional Bardeen-AdS black holes in Einstein-Gauss-Bonnet theory

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    We present a DD-dimensional Bardeen like Anti-de Sitter (AdS) black hole solution in Einstein-Gauss-Bonnet (EGB) gravity, \textit{viz}., Bardeen-EGB-AdS black holes. The Bardeen-EGB-AdS black hole has an additional parameter due to charge (ee), apart from mass (MM) and Gauss-Bonnet parameter (α\alpha). Interestingly, for each value of α\alpha, there exist a critical e=eEe = e_E which corresponds to an extremal regular black hole with degenerate horizons, while for e<eEe< e_E, it describes non-extremal black hole with two horizons. Despite the complicated solution, the thermodynamical quantities, like temperature (TT), specific heat(CC) and entropy (SS) associated with the black hole are obtained exactly. It turns out that the heat capacity diverges at critical horizon radius r+=rCr_+ = r_C, where the temperature attains maximum value and the Hawking-Page transition is achievable. Thus, we have an exact DD-dimensional regular black holes, when evaporates lead to a thermodynamical stable remnant.Comment: 25 pages, 48 figure

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    Binary coalescence from case A evolution -- mergers and blue stragglers

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    We constructed some main-sequence mergers from case A binary evolution and studied their characteristics via Eggleton's stellar evolution code. Both total mass and orbital angular momentum are conservative in our binary evolutions. Some mergers might be on the left of the ZAMS as defined by normal surface composition on a CMD because of enhanced surface helium content. The study also shows that central hydrogen content of the mergers is independent of mass. As a consequence, we fit the formula of magnitude and B-V of the mergers when they return back to thermal equilibrium with maximum error 0.29 and 0.037, respectively. Employing the consequences above, we performed Monte Carlo simulations to examine our models in NGC 2682 and NGC 2660. In NGC 2682, binary mergers from our models cover the region with high luminosity, but its importance is much less than that of AML. Our results are well-matched to the observations of NGC2660 if there is about 0.5Mo of mass loss in the merger process.Comment: 14 pages, 12 figures. accepted by MNRA

    Five dimensional rotating regular black holes and shadow

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    We present an exact five-dimensional (5D5D) rotating regular black hole metric, with a deviation parameter k≥0k\geq 0, that interpolates between the 5D5D Kerr black hole (k=0k=0) and 5D5D Kerr-Newman (r≫kr \gg k). This 5D5D rotating regular black hole is an exact solution of general relativity coupled to nonlinear electrodynamics. Interestingly, for a given value of parameter kk there exits a critical angular momentum a=aEa=a_E which corresponds to extremal rotating regular black hole with degenerate horizons, while for a<aEa<a_E, one has non-extremal rotating regular black hole with outer and inner horizons. Owing to the correction factor (e−k/r2e^{-k/r^2}), which is motivated by the quantum arguments, the ergoregion and black hole shadow are modified.Comment: 23 pages, 9 figure

    Modified Weaver-Dunn procedure, a novel approach to type-3 acromioclavicular joint dislocation

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    Even though a generally accepted opinion is present about conservative management for type 1 and type 2 acromioclavicular dislocation and surgical management for type 4 to type 6 dislocations, different opinions come under play for conservative versus surgical management in cases with acute type 3 acromioclavicular joint dislocation. We came across 20 cases of type 3 AC joint dislocation with a varied age profile (range 18 to 50 years, mean 34.4±6.5 years). Patients usually complain of pain and swelling and difficulty in moving shoulder joint. The diagnosis can be confirmed by radiographs which shows widening of AC joint &gt;2-4 mm and coracoclavicular distance &gt;5 mm and superior displacement of distal clavicle. In our series, we have treated them with modified Weaver Dunn technique. Immobilized arm in arm pouch for 3 weeks and follow up was done to assess functional outcome. In this study we present the outcome and related complications with modified Weaver Dunn technique for type 3 acromioclavicular joint dislocation

    Monodromy conjecture for semi-quasihomogeneous hypersurfaces

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    We give a proof the monodromy conjecture relating the poles of motivic zeta functions with roots of b-functions for isolated quasihomogeneous hypersurfaces, and more generally for semi-quasihomogeneous hypersurfaces. We also give a strange generalization allowing a twist by certain differential forms
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