Powerful and low-altitude winter thunderstorms in Japan provide an ideal environment to observe the high-energy atmospheric phenomena. High-energy photons have been recorded with a time scale of a minute associated with passages of thunderstorms, called “long bursts” or “gamma-ray glow”. These are bremsstrahlung radiation from relativistic electrons accelerated in strong electric field of thunderclouds. Lightning discharges also accelerate electrons and radiate high-energy gamma-rays, called “terrestrial gamma-ray flashes” when observed with satellites on orbit. Ground-based measurements have recently revealed that such gamma-rays collides with atomic nuclei of atmospheric nitrogen and oxygen, and can trigger photonuclear reaction. Such a radiation event has been observed as “short bursts” from lightning in Japan.
We present early results obtained by ALMA. With its unprecedented sensitivity, image quality and spatial resolution, ALMA has already produced a number of scientific achievements in various fields of astrophysics. In this article, we present recent results of the field of distant galaxies, star formation, and protoplanetary disks.
We review our theoretical studies on solvation effects in water and aqueous mixtures, where a trace amount of a hydrophobic solute dramatically changes the phase behavior. We discuss formation of nanobubbles with addition of oxygen in liquid water and liquid-liquid phase separation in mixtures of water-alcohol-hydrophobic solute. We present the phase diagrams on the basis of the Mansoori-Carnahan-Starling-Leland model of hardsphere mixtures.
IceCube Neutrino Observatory has launched the program of a realtime analysis framework to enable rapid follow-up observations. A～290 TeV neutrino event identified by this framework on September 22 2017 prompted various follow-up observations which revealed that this neutrino is suggested to originate in the flaring γ-ray blazar TXS0506+056 at the statistical significance of ～3σ level. This is a first identification of a likely source accelerating cosmic rays to at least several PeV. We describe how we have made these observations with IceCube Observatory in a multiwavelength follow-up campaign.
When a bias voltage is applied to a small conductor, the current fluctuates due to the partition process of electrons. This fluctuation called shot noise gives us the fundamental information of the transport process. On the other hands, the spin current is one of key issue in the spintronics field and the generation and detection of those have been intensively studied by using various materials. The letter reported the first observation of the shot noise caused by a spin current which is induced by a spin accumulation in an all-semiconductor lateral spin-valve device.