86,890 research outputs found
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
Strong Coupling Limit of Bethe Ansatz Solutions in Massive Thirring Model
We study the strong coupling limit of the Bethe ansatz solutions in the
massive Thirring model. We find analytical expressions for the energy
eigenvalues for the vacuum state as well as n-particle n- hole states. This
formula is compared with the numerical results and is found to achieve a very
good agreement.
Also, it is found that the 2-particle 2- hole and higher particle-hole states
describe n- free bosons states in this limit. The behaviors of the strong
coupling limit of the boson mass for various model calculations are examined.
We discuss an ambiguity of the coupling constant normalization due to the
current regularization.Comment: 15 pages, to appear in Ann. Phys. 281 (2000), Ma
Non-equivalence between Heisenberg XXZ spin chain and Thirring model
The Bethe ansatz equations for the spin 1/2 Heisenberg XXZ spin chain are
numerically solved, and the energy eigenvalues are determined for the
anti-ferromagnetic case. We examine the relation between the XXZ spin chain and
the Thirring model, and show that the spectrum of the XXZ spin chain is
different from that of the regularized Thirring model.Comment: 10 pages. 2figure
Simple normal crossing Fano varieties and log Fano manifolds
A projective log variety (X, D) is called "a log Fano manifold" if X is
smooth and if D is a reduced simple normal crossing divisor on X with -(K_X+D)
ample. The n-dimensional log Fano manifolds (X, D) with nonzero D are
classified in this article when the log Fano index r of (X, D) satisfies either
r\geq n/2 with \rho(X)\geq 2 or r\geq n-2. This result is a partial
generalization of the classification of logarithmic Fano threefolds by Maeda.Comment: 38 pages, minor revision; correct Theorem 2.7 and add reference
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
- …