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.

Direct Measurement of the Cosmic-Ray Proton Spectrum from 50 GeV to 10 TeV with the Calorimetric Electron Telescope on the International Space Station

Abstract: In this paper, we present the analysis and results of a direct measurement of the cosmic-ray proton spectrum with the CALET instrument onboard the International Space Station, including the detailed assessment of systematic uncertainties. The observation period used in this analysis is from October 13, 2015 to August 31, 2018 (1054 days). We have achieved the very wide energy range necessary to carry out measurements of the spectrum from 50 GeV to 10 TeV covering, for the first time in space, with a single instrument the whole energy interval previously investigated in most cases in separate subranges by magnetic spectrometers (BESS-TeV, PAMELA, and AMS-02) and calorimetric instruments (ATIC, CREAM, and NUCLEON). The observed spectrum is consistent with AMS-02 but extends to nearly an order of magnitude higher energy, showing a very smooth transition of the power-law spectral index from -2.81±0.03 (50-500 GeV) neglecting solar modulation effects (or -2.87±0.06 including solar modulation effects in the lower energy region) to -2.56±0.04 (1-10 TeV), thereby confirming the existence of spectral hardening and providing evidence of a deviation from a single power law by more than 3σ.

Comparative genome sequencing reveals genomic signature of extreme desiccation tolerance in the anhydrobiotic midge

Abstract: The African chironomid midge, Polypedilum vanderplanki, is able to withstand extreme desiccation. Here the authors sequence the genomes of a desiccation-tolerant and desiccation-sensitive species of chironomid midge and pinpoint genes that may have a role in conferring resistance to desiccation.

Astronaut's Organ Doses Inferred from Measurements in a Human Phantom Outside the International Space Station

Abstract: Reitz, G., Berger, T., Bilski, P., Facius, R., Hajek, M., Petrov, V., Puchalska, M., Zhou, D., Bossler, J., Akatov, Y., Shurshakov, V., Olko, P., Ptaszkiewicz, M., Bergmann, R., Fugger, M., Vana, N., Beaujean, R., Burmeister, S., Bartlett, D., Hager, L., Palfalvi, J., Szabo, J., O'Sullivan, D., Kitamura, H., Uchihori, Y., Yasuda, N., Nagamatsu, A., Tawara, H., Benton, E., Gaza, R., McKeever, S., Sawakuchi, G., Yukihara, E., Cucinotta, F., Semones, E., Zapp, N., Miller, J. and Dettmann, J. Astronaut's Organ Doses Inferred from Measurements in a Human Phantom Outside the International Space Station. Radiat. Res. 171, 225–235 (2009). Space radiation hazards are recognized as a key concern for human space flight. For long-term interplanetary missions, they constitute a potentially limiting factor since current protection limits for low-Earth orbit missions may be approached or even exceeded. In such a situation, an accurate risk assessment requires knowledge of equivalent doses in critical radiosensi...

The distance to the galactic center derived from infrared photometry of bulge red clump stars

Abstract: On the basis of the near-infrared observations of bulge red clump stars near the Galactic center, we have determined the galactocentric distance to be R0 = 7.52 ? 0.10 (stat) ?0.35 (sys) kpc. We observed the red clump stars at l 10 and 07 b 10 with the IRSF 1.4 m telescope and the SIRIUS camera in the H and KS bands. After extinction and population corrections, we obtained (m - M)0 = 14.38 ? 0.03 (stat) ? 0.10 (sys). The statistical error is dominated by the uncertainty of the intrinsic local red clump stars' luminosity. The systematic error is estimated to be ?0.10, including uncertainties in extinction and population correction, zero point of photometry, and the fitting of the luminosity function of the red clump stars. Our result, R0 = 7.52 kpc, is in excellent agreement with the distance determined geometrically with the star orbiting the massive black hole in the Galactic center. The recent result based on the spatial distribution of globular clusters is also consistent with our result. In addition, our study exhibits that the distance determination to the Galactic center with the red clump stars, even if the error of the population correction is taken into account, can achieve an uncertainty of about 5%, which is almost the same level as that in recent geometrical determinations.