132,569 research outputs found

    A Danilov-type formula for toric origami manifolds via localization of index

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    We give a direct geometric proof of a Danilov-type formula for toric origami manifolds by using the localization of Riemann-Roch number.Comment: 30 pages, 8 figures : Revision of the introduction. Added references : Typos corrected. Construction in Section 4.1 simplified. Proofs of Lemma 6.2 and Theorem 6.12 corrected. Acknowledgement for the referee added : Final version, to appear in Osaka Journal of Mathematic

    Non-thermal Emissions from Cool Cores Heated by Cosmic-Rays in Galaxy Clusters

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    We study non-thermal emissions from cool cores in galaxy clusters. We adopted a recent model, in which cosmic-rays (CRs) prevail in the cores and stably heat them through CR streaming. The non-thermal emissions come from the interaction between CR protons and intracluster medium (ICM). Comparison between the theoretical predictions and radio observations shows that the overall CR spectra must be steep, and most of the CRs in the cores are low-energy CRs. Assuming that the CRs are injected through AGN activities, we study the nature of the shocks that are responsible for the CR acceleration. The steep CR spectra are likely to reflect the fact that the shocks travel in hot ICM with fairly small Much numbers. We also study the dependence on the CR streaming velocity. The results indicate that synchrotron emissions from secondary electrons should be observed as radio mini-halos in the cores. In particular, low-frequency observations (e.g. LOFAR) are promising. On the other hand, the steepness of the spectra makes it difficult to detect non-thermal X-ray and gamma-ray emissions from the cores. The low-energy CRs may be heating optical filaments observed in the cores.Comment: Accepted for publication in Ap

    Gravitational Waves from a Particle in Circular Orbits around a Schwarzschild Black Hole to the 22nd Post-Newtonian Order

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    We extend our previous results of the 14th post-Newtonian (PN) order expansion of gravitational waves for a test particle in circular orbits around a Schwarzschild black hole to the 22PN order, i.e. v44v^{44} beyond the leading Newtonian approximation where vv is the orbital velocity of a test particle. Comparing our 22PN formula for the energy flux with high precision numerical results, we find that the relative error of the 22PN flux at the innermost stable circular orbit is about 10510^{-5}. We also estimate the phase difference between the 22PN waveforms and numerical waveforms after a two-year inspiral. We find that the dephase is about 10910^{-9} for μ/M=104\mu/M=10^{-4} and 10210^{-2} for μ/M=105\mu/M=10^{-5} where μ\mu is the mass of the compact object and MM the mass of the central supermassive black hole. Finally, we construct a hybrid formula of the energy flux by supplementing the 4PN formula of the energy flux for circular and equatorial orbits around a Kerr black hole with all the present 22PN terms for the case of a Schwarzschild black hole. Comparing the hybrid formula with the the full numerical results, we examine the performance of the hybrid formula for the case of Kerr black hole.Comment: 22 pages, additional datafiles are available at <a href="http://www2.yukawa.kyoto-u.ac.jp/~misao/BHPC/calcs.html">this http URL</a

    Holographic Entanglement Entropy for d=4 N=2 SCFTs in F-theory

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    We compute the holographic entanglement entropy in the gravity with higher curvature terms dual to d=4 N=2 SCFTs in F-theory using the method proposed in arXiv:1011.5819. The log term of this entanglement entropy reproduces the A-type anomaly of the dual SCFTs in F- theory using the gravity dual with the higher derivative term, which, using the field redefinition, can be transformed to the Gauss-Bonnet term in the subleading order of a derivative expansion. Our analysis shows that the 1/N^2 correction for the central charges should be produced from the gravity including higher derivative terms up to curvature squared terms. To obtain consistent results, we discuss the holographic c-theorem.Comment: 19 pages; v3: references added and improved version with section 4.1 clarifie
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