Propagation of Ultra-high-energy Cosmic Rays in Galactic Magnetic Field

The propagation trajectories of ultra-high-energy cosmic rays (UHECRs) are inevitably affected by Galactic magnetic field (GMF). Because of the inevitability, the importance of the studies of the propagation in GMF have increased to interpret the results of recent UHECR experiments. This article reviews the effects of GMF to the propagation and arrival directions of UHECRs and introduces recent studies to constrain UHECR sources.Comment: 6 pages, 3 figures. An invited review article to appear in the Proceedings of the International Workshop on the Recent Progress of Ultra-high Energy Cosmic Ray Observation (UHECR2010), Nagoya, Japan, 201

Pigou's theory of business cycle as an inquiry into unemployment: on the relative effects of the gold standard and the wage rigidity in the twenties

In this paper I examine A. C. Pigou's views on the unemployment policies, based on the premise that, as he himself acknowledged, his theory of business fluctuations was one integral part of his whole thought about unemployment. In his Industrial Fluctuations (1927), Pigou gave the most extensive treatment to the monetary policy among the measures against business fluctuations. There he advocated more prompt and smooth action by the Bank of England in order to effectively stabilize the movement of general prices and the economy as a whole. In order for its action not to be affected by external monetary shocks, he suggested the withdrawal from the gold standard should the public opinion and international diplomatic relations allow it. Pigou, meanwhile, placed much less importance on wage adjustment as a palliative against business cycle. The recent studies direct attention to the fact that Pigou pointed out that after World War I money wages were made rigid by such factors as contemporary institutional changes in labor markets. This picture, however, lacks a more important element of his thought: the monetary cause due to the gold standard on the prewar parity. Putting his indirect remarks on this influence together, I argue that Pigou was well aware of the monetary situation and seemed to place greater importance on the monetary influence than the wage rigidity.history of economic thought, Pigou, unemployment

Estimation Prospects of the Source Number Density of Ultra-high-energy Cosmic Rays

We discuss the possibility of accurately estimating the source number density of ultra-high-energy cosmic rays (UHECRs) using small-scale anisotropy in their arrival distribution. The arrival distribution has information on their source and source distribution. We calculate the propagation of UHE protons in a structured extragalactic magnetic field (EGMF) and simulate their arrival distribution at the Earth using our previously developed method. The source number density that can best reproduce observational results by Akeno Giant Air Shower Array is estimated at about $10^{-5} {\rm Mpc}^{-3}$ in a simple source model. Despite having large uncertainties of about one order of magnitude, due to small number of observed events in current status, we find that more detection of UHECRs in the Auger era can sufficiently decrease this so that the source number density can be more robustly estimated. 200 event observation above $4 \times 10^{19} {\rm eV}$ in a hemisphere can discriminate between $10^{-5}$ and $10^{-6} {\rm Mpc}^{-3}$. Number of events to discriminate between $10^{-4}$ and $10^{-5} {\rm Mpc}^{-3}$ is dependent on EGMF strength. We also discuss the same in another source model in this paper.Comment: 19 pages, 8 figures, accepted for publication in Astroparticle Physic

The Production of Ultra High Energy Cosmic Rays during the Early Epochs of Radio-loud AGN

Powerful radio-loud active galactic nuclei (AGN) with large Mpc-scale jets have been theoretically motivated as emitters of high-energy cosmic rays. Recent radio observations have established a populous class of young radio-loud galaxies with compact ($< 1$ kpc) symmetric jets that are morphologically similar to large-scale AGNs. We show that these compact AGNs, so-called compact symmetric objects (CSOs), can accelerate protons up to $10^{20}$ eV at their hot spots via a Fermi type mechanism on the assumption of efficient acceleration. The required magnetic field strengths are comparable to those derived from the minimum energy condition. We further show that the accelerated protons can escape through the photon fields of the cocoon without significant energy loss. However, the local number density of powerful CSOs is insufficient for CSOs to power the entire observed flux of ultra-high-energy cosmic rays, providing maximally only a few percent. A heavy composition of UHECRs allows more CSOs to accelerate particles to UHECR energies, but escaping the cocoon is difficult. We comment on a method that may test CSOs as UHECR sources.Comment: 7 pages, 3 figure