Aoyama Gakuin University

About: Aoyama Gakuin University is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Superconductivity & Thin film. The organization has 3494 authors who have published 6419 publications receiving 115648 citations. The organization is also known as: Aoyama gakuin daigaku.

Non-Gaussianity, Spectral Index and Tensor Modes in Mixed Inflaton and Curvaton Models

Abstract: We study non-Gaussianity, the spectral index of primordial scalar fluctuations, and tensor modes in models where fluctuations from the inflaton and the curvaton can both contribute to the present cosmic density fluctuations. Even though simple single-field inflation models generate only tiny non-Gaussianity, if we consider such a mixed scenario, large non-Gaussianity can be produced. Furthermore, we study the inflationary parameters such as the spectral index and the tensor-to-scalar ratio in this kind of models and discuss in what cases models predict the spectral index and tensor modes allowed by the current data while generating large non-Gaussianity, which may have many implications for model-buildings of the inflationary universe.

Gas Slit Camera (GSC) onboard MAXI on ISS

Abstract: The Gas Slit Camera (GSC) is an X-ray instrument on the MAXI (Monitor of All-sky X-ray Image) mission on the International Space Station. It is designed to scan the entire sky every 92-minute orbital period in the 2‐30 keV band and to achieve the highest sensitivity among the X-ray all-sky monitors ever flown so far. The GSC employs large-area position-sensitive proportional counters with the total detector area of 5350 cm 2 . The on-board data processor has functions to format telemetry data as well as to control the high voltage of the proportional counters to protect them from the particle irradiation. The paper describes the instruments, on-board data processing, telemetry data formats, and performance specifications expected from the ground calibration tests.

Gamma-rays from molecular clouds illuminated by cosmic rays escaping from interacting supernova remnants

Abstract: Recently, the gamma-ray telescopes AGILE and Fermi observed several middle-aged supernova remnants (SNRs) interacting with molecular clouds. It is likely that their gamma-rays arise from the decay of neutral pions produced by the inelastic collision between cosmic rays (CRs) and nucleons, which suggests that SNRs make the bulk of Galactic CRs. In this paper, we provide the analytical solution of the distribution of CRs that have escaped from a finite-size region, which naturally explains observed broken power-law spectra of the middle-aged SNRs. In addition, the typical value of the break energy of the gamma-ray spectrum, 1–10 GeV, is naturally explained from the fact that the stellar wind dynamics shows a separation between the molecular clouds and the explosion centre of about 10 pc. We find that the runaway-CR spectrum of the four middle-aged SNRs (W51C, W28, W44 and IC 443) interacting with molecular clouds could be the same, even though it leads to different gamma-ray spectra. This result is consistent with that of recent studies of Galactic CR propagation, and supports that SNRs are indeed the sources of Galactic CRs.

Rational design and crystal structure determination of a 3-D metal-organic jungle-gym-like open framework.

Abstract: A new three-dimensional (3-D) jungle-gym-like open metal-organic framework has been synthesized from a two-dimensional (2-D) layer compound using a heterogeneous pillar insertion reaction. Both the starting 2-D layer and the resulting 3-D open compounds have been characterized using X-ray crystallography.