132,569 research outputs found
A Danilov-type formula for toric origami manifolds via localization of index
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
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
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. beyond the leading
Newtonian approximation where 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 . 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 for and
for where is the mass of the compact object and 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
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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