Japan Aerospace Exploration Agency

About: Japan Aerospace Exploration Agency is a facility organization based out in Tokyo, Japan. It is known for research contribution in the topics: Galaxy & Telescope. The organization has 4327 authors who have published 12054 publications receiving 208330 citations.

Extended Measurement of the Cosmic-Ray Electron and Positron Spectrum from 11 GeV to 4.8 TeV with the Calorimetric Electron Telescope on the International Space Station.

Abstract: Extended results on the cosmic-ray electron + positron spectrum from 11 GeV to 4.8 TeV are presented based on observations with the Calorimetric Electron Telescope (CALET) on the International Space Station utilizing the data up to November 2017. The analysis uses the full detector acceptance at high energies, approximately doubling the statistics compared to the previous result. CALET is an all-calorimetric instrument with a total thickness of 30 X_{0} at normal incidence and fine imaging capability, designed to achieve large proton rejection and excellent energy resolution well into the TeV energy region. The observed energy spectrum in the region below 1 TeV shows good agreement with Alpha Magnetic Spectrometer (AMS-02) data. In the energy region below ∼300 GeV, CALET's spectral index is found to be consistent with the AMS-02, Fermi Large Area Telescope (Fermi-LAT), and Dark Matter Particle Explorer (DAMPE), while from 300 to 600 GeV the spectrum is significantly softer than the spectra from the latter two experiments. The absolute flux of CALET is consistent with other experiments at around a few tens of GeV. However, it is lower than those of DAMPE and Fermi-LAT with the difference increasing up to several hundred GeV. The observed energy spectrum above ∼1 TeV suggests a flux suppression consistent within the errors with the results of DAMPE, while CALET does not observe any significant evidence for a narrow spectral feature in the energy region around 1.4 TeV. Our measured all-electron flux, including statistical errors and a detailed breakdown of the systematic errors, is tabulated in the Supplemental Material in order to allow more refined spectral analyses based on our data.

Gas turbine combustor

Abstract: The present invention provides a gas turbine combustor which makes it possible to achieve both a high combustion efficiency and low NOx emissions characteristics over a wide output power range without using a device that can vary the flow rate of the air used for combustion, by burning a lean mixture using high-temperature burned gas. The gas turbine combustor 10 comprises pre-mixture injection tubes 16 which conduct a mixture of fuel and air into a combustion chamber 11 . The mixture from the pre-mixture injection tubes 16 is injected toward burned gas 19 a present on the downstream side of the flame 19 , which is injected from burners 15 that open into the combustion chamber 11 , and this mixture is mixed with the burned gas 19 a . Even in a mixture which is leaner than the lower limit of inflammability, the radicals in the burned gas 19 a are effective in initiating reactions, so that the combustion of the mixture can be started. Since the burned gas has a lower oxygen concentration than fresh mixture, and since the pre-mixture is dispersed in space, the generation of NOx can be suppressed.

Near-Infrared and Mid-Infrared Spectroscopy with the Infrared Camera (IRC) for AKARI

Abstract: The Infrared Camera (IRC) is one of the two instruments on board the AKARI satellite. In addition to deep imaging from 1.8–26.5μm for the pointed observation mode of the AKARI, it has a spectroscopic capability in its spectral range. By replacing the imaging filters by transmission-type dispersers on the filter wheels, it provides low-resolution (λ/δλ ∼ 20–120) spectroscopy with slits or in a wide imaging field-of-view (approximately 10×10). The IRC spectroscopic mode is unique in space infrared missions in that it has the capability to perform sensitive wide-field spectroscopic surveys in the nearand midinfrared wavelength ranges. This paper describes specifications of the IRC spectrograph and its in-orbit performance.

X-Ray Temperature and Mass Measurements to the Virial Radius of Abell 1413 with Suzaku

Abstract: We present X-ray observations of the northern outskirts of the relaxed galaxy cluster A 1413 with Suzaku, whose XIS instrument has the low intrinsic background needed to make measurements of these low surface brightness regions. We excised 15 point sources superimposed on the image above a flux of 1 10 erg cm 2 s 1 (2–10 keV) using XMM-Newton and Suzaku images of the cluster. We quantified all known systematic errors as part of our analysis, and showed that our statistical errors encompass them for the most part. Our results extend previous measurements with Chandra and XMM-Newton, and show a significant temperature drop to about 3 keV at the virial radius, r200. Our entropy profile in the outer region (>0.5r200) joins smoothly onto that of XMM-Newton, and shows a flatter slope compared with simple models, similar to a few other clusters observed at the virial radius. The integrated mass of the cluster at the virial radius is approximately 7.5 10Mˇ, and varies by about 30%, depending on the particular method used to measure it.

X-ray spectral study of the photoionized stellar wind in Vela X-1

Abstract: We present results from quantitative modeling and spectral analysis of the high-mass X-ray binary system Vela X-1 obtained with the Chandra HETGS. The spectra exhibit emission lines from H- and He-like ions driven by photoionization, as well as fluorescent emission lines from several elements in lower charge states. The properties of these X-ray lines are measured with the highest accuracy to date. In order to interpret and make full use of the data, we have developed a simulator, which calculates the ionization structure of a stellar wind and performs Monte Carlo simulations of X-ray photons propagating through the wind. From comparisons of the observed spectra with results from the simulator, we are able to find the ionization structure and the geometrical distribution of material in the stellar wind that can reproduce the observed spectral line intensities and continuum shapes remarkably well. We find that the stellar wind profile can be represented by a CAK model with a star mass-loss rate of (1.5-2.0) × 10-6 M☉ yr-1, assuming a terminal velocity of 1100 km s-1. It is found that a large fraction of emission lines from highly ionized ions are formed in the region between the neutron star and the companion star. We also find that the fluorescent lines must be produced in at least three distinct regions: the extended stellar wind, reflection off the stellar photosphere, and in a distribution of dense material partially covering and possibly trailing the neutron star, which may be associated with an accretion wake. Finally, from detailed analysis of the emission-line profiles, we demonstrate that the stellar wind dynamics is affected by X-ray photoionization.