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21 results on '"Ogasaka Y"'

3. InFOCμS Hard X-ray Imaging Telescope

Author

Tueller, J., Krimm, H. A., Okajima, T., Barthelmy, S. D., Owens, S. M., Serlemitsos, P. J., Soong, Y., Chan, K.-W., Ogasaka, Y., Shibata, R., Tamura, K., Furuzawa, A., Tawara, Y., Kunieda, H., and Yamashita, K.

Published
2005
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9. X-ray identification of the soft gamma-ray repeater 1806 - 20

Author

Murakami, T., Tanaka, Y., Kulkarni, S.R., Ogasaka, Y., Sonobe, T., Ogawara, Y., Aoki, T., and Yoshida, A.

Subjects
Gamma rays -- Research, Pulsars -- Research, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

The study of the gamma ray burst from SGR 1806-20 reveals that the source is a neutron star. The bursts are detected by the X-ray satellite ASCA, which identifies the bursts with an X-ray source AX 1805.7 to 2025. The BATSE instrument in the Gamma Ray Observatory also detects the bursts at the same time. The studies indicate the presence of a young pulsar at the center of SGR 1806-20.

Published
1994

20. Hard X-ray focusing optics up to 80 keV for the future missions

Author

Okajima, T., Tawara, Y., Ogasaka, Y., Tamura, K., Furuzawa, A., Yamashita, K., and Kunieda, H.

Subjects
*X-rays, *SPACE astronomy, *TELESCOPES, *ASTRONOMY
Abstract

X-ray telescopes have been providing high sensitivity X-ray observations in numerous missions. For X-ray telescopes in the future, one of the key technologies is to expand the energy band beyond 10 keV. We designed depth-graded multilayer, so-called supermirrors, for a hard X-ray telescope in the energy band up to 40 keV using lightweight thin-foil optics. They were successfully flown in a balloon flight and obtained a hard X-ray image of Cyg X-1 in the 20–40 keV band. Now supermirrors are promising to realize a hard X-ray telescope. We have estimated the performance of a hard X-ray telescope using a platinum–carbon supermirror for future satellite missions, such as NeXT (Japan) and XEUS (Europe). According to calculations, they will have a significant effective area up to 80 keV, and their effective areas will be more than 280 cm2 even at 60 keV. Limiting sensitivity will be down to 1.7 × 10-13 erg cm-2 s-1 in the 10–80 keV band at a 100 ks observation. In this paper, we present the results of the balloon experiment with the first supermirror flown and projected effective areas of hard X-ray telescopes and action items for future missions. [Copyright &y& Elsevier]

Published
2004
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21. Development of thin-foil substrates for a large X-ray telescope

Author

Awaki, H., Heike, K., Misao, Y., Tawara, Y., Ogasaka, Y., Kunieda, H., Ohmori, H., Lin, W., Moriyasu, S., Ueno, Y., Morita, S., Katahira, K., Liu, C., Honda, H., and Shioya, S.

Subjects
*X-rays, *TELESCOPES, *ASTRONOMY, *OPTICAL instruments
Abstract

We have built a prototype of thin-foil substrates for the future mission with a large X-ray telescope. In future X-ray missions, the understanding of the early universe to reveal the evolution of the universe will become an important issue. For this purpose, large telescopes with high-spatial resolution up to 10′′ are required. Using a stamping die with high accuracy, we have successfully press-formed thin-foil substrates into an almost accurate form of the Wolter type-I optics, which reflect X-rays twice with their confocal paraboloidal and hyperboloidal reflectors. The accuracy of the shape has reached to <15 μm. [Copyright &y& Elsevier]

Published
2004
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