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122 results on '"Tsushima, I"'

1. Energy determination in the Akeno Giant Air Shower Array experiment

Author

Takeda, M., Sakaki, N., Honda, K., Chikawa, M., Fukushima, M., Hayashida, N., Inoue, N., Kadota, K., Kakimoto, F., Kamata, K., Kawaguchi, S., Kawakami, S., Kawasaki, Y., Kawasumi, N., Mahrous, A. M., Mase, K., Mizobuchi, S., Morizane, Y., Nagano, M., Ohoka, H., Osone, S., Sasaki, M., Sasano, M., Shimizu, H. M., Shinozaki, K., Teshima, M., Torii, R., Tsushima, I., Uchihori, Y., Yamamoto, T., Yoshida, S., and Yoshii, H.

Subjects
Astrophysics
Abstract

Using data from more than ten-years of observations with the Akeno Giant Air Shower Array (AGASA), we published a result that the energy spectrum of ultra-high energy cosmic rays extends beyond the cutoff energy predicted by Greisen, and Zatsepin and Kuzmin. In this paper, we reevaluate the energy determination method used for AGASA events with respect to the lateral distribution of shower particles, their attenuation with zenith angle, shower front structure, delayed particles observed far from the core and other factors. The currently assigned energies of AGASA events have an accuracy of $\pm$25% in event-reconstruction resolution and $\pm$18% in systematic errors around 10$^{20}$eV. This systematic uncertainty is independent of primary energy above 10$^{19}$eV. Based on the energy spectrum from 10$^{14.5}$eV to a few times 10$^{20}$eV determined at Akeno, there are surely events above 10$^{20}$eV and the energy spectrum extends up to a few times 10$^{20}$eV without a GZK-cutoff., Comment: accepted to Astroparticle Physics, 29pages, 17+1 figures, elsart.cls The AGASA exposure is 5.1x10^16 m2 sr s until July 2002

Published
2002
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2. Updated AGASA event list above 4x10^19eV

Author

Hayashida, N., Honda, K., Inoue, N., Kadota, K., Kakimoto, F., Kakizawa, S., Kamata, K., Kawaguchi, S., Kawasaki, Y., Kawasumi, N., Kusano, E., Mahrous, A. M., Mase, K., Minagawa, T., Nagano, M., Nishikawa, D., Ohoka, H., Osone, S., Sakaki, N., Sasaki, M., Shinozaki, K., Takeda, M., Teshima, M., Torii, R., Tsushima, I., Uchihori, Y., Yamamoto, T., Yoshida, S., and Yoshii, H.

Subjects
Astrophysics
Abstract

After our Ap.J. publication of the Akeno Giant Air Shower Array (AGASA) results in 1999 (Takeda et al., 1999), we observed nine events with energies above 4 $\times$ 10$^{19}$eV until May 2000. This short report lists the coordinates of these events, and shows the updated energy spectrum and arrival direction map. The analysis was carried out with the same procedure employed in the Ap.J. publication., Comment: 6 pages, 2 figures, appendix for ApJ 522(1999) 225

Published
2000

3. The Anisotropy of Cosmic Ray Arrival Direction around 10^18eV

Author

Hayashida, N., Honda, K., Inoue, N., Kadota, K., Kakimoto, F., Kakizawa, S., Kamata, K., Kawaguchi, S., Kawasaki, Y., Kawasumi, N., Kusano, E., Matsubara, Y., Mase, K., Minagawa, T., Murakami, K., Nagano, M., Nishikawa, D., Ohoka, H., Osone, S., Sakaki, N., Sasaki, M., Sasano, M., Shinozaki, K., Takeda, M., Teshima, M., Torii, R., Tsushima, I., Uchihori, Y., Yamamoto, T., Yoshida, S., Yoshii, H., and Collaboration, The AGASA

Subjects
Astrophysics
Abstract

Anisotropy in the arrival directions of cosmic rays around 10^{18}eV is studied using data from the Akeno 20 km^2 array and the Akeno Giant Air Shower Array (AGASA), using a total of about 216,000 showers observed over 15 years above 10^{17}eV. In the first harmonic analysis, we have found significant anisotropy of $\sim$ 4 % around 10^{18}eV, corresponding to a chance probability of $\sim 10^{-5}$ after taking the number of independent trials into account. With two dimensional analysis in right ascension and declination, this anisotropy is interpreted as an excess of showers near the directions of the Galactic Center and the Cygnus region. This is a clear evidence for the existence of the galactic cosmic ray up to the energy of 10^{18}eV. Primary particle which contribute this anisotropy may be proton or neutron., Comment: 4pages, three figures, to appear in Procedings of 26th ICRC(Salt Lake City)

Published
1999
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4. Small-scale anisotropy of cosmic rays above 10^19eV observed with the Akeno Giant Air Shower Array

Author

Takeda, M., Hayashida, N., Honda, K., Inoue, N., Kadota, K., Kakimoto, F., Kamata, K., Kawaguchi, S., Kawasaki, Y., Kawasumi, N., Kusano, E., Matsubara, Y., Murakami, K., Nagano, M., Nishikawa, D., Ohoka, H., Osone, S., Sakaki, N., Sasaki, M., Shinozaki, K., Souma, N., Teshima, M., Torii, R., Tsushima, I., Uchihori, Y., Yamamoto, T., Yoshida, S., and Yoshii, H.

Subjects
Astrophysics
Abstract

With the Akeno Giant Air Shower Array (AGASA), 581 cosmic rays above 10^19eV, 47 above 4 x 10^19eV, and 7 above 10^20eV are observed until August 1998. Arrival direction distribution of these extremely high energy cosmic rays has been studied. While no significant large-scale anisotropy is found on the celestial sphere, some interesting clusters of cosmic rays are observed. Above 4 x 10^19eV, there are one triplet and three doublets within separation angle of 2.5^o and the probability of observing these clusters by a chance coincidence under an isotropic distribution is smaller than 1 %. Especially the triplet is observed against expected 0.05 events. The cos(\theta_GC) distribution expected from the Dark Matter Halo model fits the data as well as an isotropic distribution above 2 x 10^19eV and 4 x 10^19eV, but is a poorer fit than isotropy above 10^19eV. Arrival direction distribution of seven 10^20eV cosmic rays is consistent with that of lower energy cosmic rays and is uniform. Three of seven are members of doublets above about 4 x 10^19eV., Comment: 40 pages, 12 figure, AASTeX *** Authors found a typo on Table 2 -- Energy of event 94/07/06 ***

Published
1999
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5. Extension of the Cosmic-Ray Energy Spectrum Beyond the Predicted Greisen-Zatsepin-Kuz'min Cutoff

Author

Takeda, M., Hayashida, N., Honda, K., Inoue, N., Kadota, K., Kakimoto, F., Kamata, K., Kawaguchi, S., Kawasaki, Y., Kawasumi, N., Kitamura, H., Kusano, E., Matsubara, Y., Murakami, K., Nagano, M., Nishikawa, D., Ohoka, H., Sakaki, N., Sasaki, M., Shinozaki, K., Souma, N., Teshima, M., Torii, R., Tsushima, I., Uchihori, Y., Yamamoto, T., Yoshida, S., and Yoshii, H.

Subjects
Astrophysics
Abstract

The cosmic-ray energy spectrum above 10^{18.5} eV is reported using the updated data set of the Akeno Giant Air Shower Array (AGASA) from February 1990 to October 1997. The energy spectrum extends beyond 10^{20} eV and the energy gap between the highest energy event and the others is being filled up with recently observed events. The spectral shape suggests the absence of the 2.7 K cutoff in the energy spectrum or a possible presence of a new component beyond the 2.7 K cutoff., Comment: to be published in PRL, 3 figures, REVTEX format

Published
1998
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6. The Anisotropy of Cosmic Ray Arrival Directions around 10$^{18}$eV

Author

AGASA Collaboration, Hayashida, N., Honda, K., Inoue, N., Kadota, K., Kakimoto, F., Kamata, K., Kawaguchi, S., Kawasaki, Y., Kawasumi, N., Kitamura, H., Kusano, E., Matsubara, Y., Murakami, K., Nagano, M., Nishikawa, D., Ohoka, H., Sakaki, N., Sasaki, M., Shinozaki, K., Souma, N., Takeda, M., Teshima, M., Torii, R., Tsushima, I., Uchihori, Y., Yamamoto, T., Yoshida, S., and Yoshii, H.

Subjects
Astrophysics
Abstract

Anisotropy in the arrival directions of cosmic rays with energies above 10$^{17}$eV is studied using data from the Akeno 20 km$^2$ array and the Akeno Giant Air Shower Array (AGASA), using a total of about 117,000 showers observed during 11 years. In the first harmonic analysis, we have found strong anisotropy of $\sim$ 4% around 10$^{18}$eV, corresponding to a chance probability of 0.2%. With two dimensional analysis in right ascension and declination, this anisotropy is interpreted as an excess of showers near the directions of the Galactic Center and the Cygnus region., Comment: 17 pages with 16 figures, http://www.icrr.u-tokyo.ac.jp/~erina/English.html

Published
1998
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7. The Detection of TeV Gamma Rays from Crab using the Telescope Array Prototype

Author

Aiso, S., Chikawa, M., Hayashi, Y., Hayashida, N., Hibino, K., Hirasawa, H., Honda, K., Hotta, N., Inoue, N., Ishikawa, F., Ito, N., Kabe, S., Kajino, F., Kashiwagi, T., Kawakami, S., Kawasaki, Y., Kawasumi, N., Kitamura, H., Kuramochi, K., Kurata, K., Kusano, E., Lafoux, H., Loh, E. C., Matsubara, Y., Matsuyama, T., Mizumoto, Y., Mizutani, K., Nagano, M., Nishikawa, D., Nishimura, J., Nishizawa, M., Ouchi, T., Ohoka, H., Ohnishi, M., Saito, To., Sakaki, N., Sakata, M., Sakumoto, K., Sasaki, M., Sasano, M., Shimodaira, H., Shiomi, A., Sokolsky, P., Sugiyama, T., Takahashi, T., Taylor, S., Teshima, M., Tsushima, I., Uchihori, Y., Yamamoto, T., Yamamoto, Y., Yoshida, S., Yoshii, H., and Yuda, T.

Subjects
Astrophysics
Abstract

The Telescope Array prototype detectors were installed at Akeno Observatory and at the Utah Fly's Eye site. Using these detectors, we have observed the Crab Nebula and AGN's since the end of 1995. The successful detections of TeV gamma rays from Crab Nebula and Mkn501 are reported., Comment: 4 pages, 5 figures, contribution to 25th ICRC Durban

Published
1997

10. Energy determination in the Akeno Giant Air Shower Array experiment

Author

Takeda, M., Sakaki, N., Honda, K., Chikawa, M., Fukushima, M., Hayashida, N., Inoue, N., Kadota, K., Kakimoto, F., Kamata, K., Kawaguchi, S., Kawakami, S., Kawasaki, Y., Kawasumi, N., Mahrous, A.M., Mase, K., Mizobuchi, S., Morizane, Y., Nagano, M., Ohoka, H., Osone, S., Sasaki, M., Sasano, M., Shimizu, H.M., Shinozaki, K., Teshima, M., Torii, R., Tsushima, I., Uchihori, Y., Yamamoto, T., Yoshida, S., and Yoshii, H.

Published
2003
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14. The anisotropy of cosmic ray arrival directions around 1018 eV

Author

Hayashida, N., Honda, K., Inoue, N., Kadota, K., Kakimoto, F., Kakizawa, S., Kamata, K., Kawaguchi, S., Kawasaki, Y., Kawasumi, N., Kusano, E., Matsubara, Y., Mase, K., Minagawa, T., Murakami, K., Nagano, M., Nishikawa, D., Ohoka, H., Osone, S., Sakaki, N., Sasaki, M., Sasano, M., Shinozaki, K., Takeda, M., Teshima, M., Torii, R., Tsushima, I., Uchihori, Y., Yamamoto, T., Yoshida, S., Yoshii, H., and Collaboration, The AGASA

Subjects
Physics, Air shower, Astrophysics (astro-ph), Galactic Center, FOS: Physical sciences, Astronomy and Astrophysics, Cosmic ray, Akeno Giant Air Shower Array, Astrophysics, Anisotropy, Right ascension, Declination
Abstract

Anisotropy in the arrival directions of cosmic rays around 10^{18}eV is studied using data from the Akeno 20 km^2 array and the Akeno Giant Air Shower Array (AGASA), using a total of about 216,000 showers observed over 15 years above 10^{17}eV. In the first harmonic analysis, we have found significant anisotropy of $\sim$ 4 % around 10^{18}eV, corresponding to a chance probability of $\sim 10^{-5}$ after taking the number of independent trials into account. With two dimensional analysis in right ascension and declination, this anisotropy is interpreted as an excess of showers near the directions of the Galactic Center and the Cygnus region. This is a clear evidence for the existence of the galactic cosmic ray up to the energy of 10^{18}eV. Primary particle which contribute this anisotropy may be proton or neutron., Comment: 4pages, three figures, to appear in Procedings of 26th ICRC(Salt Lake City)

Published
1999

15. On An Intermittent Component of Hadron-less Air Showers Observed at Mt.Chacaltaya

Author

Nishida, T., Yoshimura, S., Matano, T., Honda, K., Tsushima, I., Kawasumi, N., Hashimoto, K., Inoue, N., Mori, K., Ticona, R., Martinic, N., Aliaga, Z., Ginroda, N., and Zapata, J.

Subjects
Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, High Energy Physics::Experiment, Physics::Atmospheric and Oceanic Physics
Abstract

Observation of UHE gamma-rays has been carried out at the hiest altitude with SYS air shower array from Feb. 1986. We study the time interval distribution of any successive air showers arriving from the same direction to find an excess on the celestial coordinate. The preliminary results from hadron-less air showers are shown in this paper.

Published
1993

18. A halo event observed by hybrid detector at Mt. Chacaltaya

Author

Aoki, H, Hashimoto, K, Honda, K, Inoue, N, Kawasumi, N, Martinic, N J, Navia, C E, Ohmori, N, Ohsawa, A, Oliveira, L C, Shinozaki, K, Tamada, M, Ticona, R, and Tsushima, I

Subjects
Astrophysics and Astronomy
Published
2001

27. The cosmic ray energy spectrum above 10$^{19}$ eV determined by AGASA

Author

Doi, T, Hayashida, N, Honda, K, Honda, M, Inoue, N, Kadota, K, Kakimoto, F, Kamata, K, Kawaguchi, S, Kawasumi, N, Matsubara, Y, Murakami, K, Nagano, M, Ohoka, H, Takeda, M, Teshima, M, Tsushima, I, Uchihori, Y, Yoshida, S, and Yoshii, H

Subjects
Astrophysics and Astronomy
Published
1997

28. Point source search for cosmic rays above 3 x 10$^{17}$ eV by AGASA

Author

Doi, T, Hayashida, N, Honda, K, Honda, M, Inoue, N, Kadota, K, Kakimoto, F, Kamata, K, Kawaguchi, S, Kawasumi, N, Matsubara, Y, Murakami, K, Nagano, M, Ohoka, H, Takeda, M, Teshima, M, Tsushima, I, Yoshida, S, and Yoshii, H

Subjects
Astrophysics and Astronomy
Published
1996

37. Lateral distribution of high energy hadrons and gamma ray in air shower cores observed with emulsion chambers

Author

Matano, T, Machida, M, Kawasumi, N, Tsushima, I, Honda, K, Hashimoto, K, Navia, C. E, Matinic, N, and Aquirre, C

Subjects
Space Radiation
Abstract

A high energy event of a bundle of electrons, gamma rays and hadronic gamma rays in an air shower core were observed. The bundles were detected with an emulsion chamber with thickness of 15 cm lead. This air shower is estimated to be initiated with a proton with energy around 10 to the 17th power to 10 to the 18th power eV at an altitude of around 100 gmc/2. Lateral distributions of the electromagnetic component with energy above 2 TeV and also the hadronic component of energy above 6 TeV of this air shower core were determined. Particles in the bundle are produced with process of the development of the nuclear cascade, the primary energy of each interaction in the cascade which produces these particles is unknown. To know the primary energy dependence of transverse momentum, the average products of energy and distance for various average energies of secondary particles are studied.

Published
1985

39. A halo event observed by hybrid detectors at Mt. Chacaltaya

Author

Aoki, H., primary, Hashimoto, K., additional, Honda, K., additional, Inoue, N., additional, Kawasumi, N., additional, Martinic, N., additional, Navia, C., additional, Ohmori, N., additional, Ohsawa, A., additional, Oliveira, L.C., additional, Shinozaki, K., additional, Tamada, M., additional, Ticona, R., additional, and Tsushima, I., additional

Published
2003
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40. Upper Limit on Gamma-Ray Flux above 10[TSUP]19[/TSUP] [CLC]e[/CLC]V Estimated by the Akeno Giant Air Shower Array Experiment

Author

Shinozaki, K., primary, Chikawa, M., additional, Fukushima, M., additional, Hayashida, N., additional, Inoue, N., additional, Honda, K., additional, Kadota, K., additional, Kakimoto, F., additional, Kamata, K., additional, Kawaguchi, S., additional, Kawakami, S., additional, Kawasaki, Y., additional, Kawasumi, N., additional, Mahrous, A. M., additional, Mase, K., additional, Mizobuchi, S., additional, Morizane, Y., additional, Nagano, M., additional, Ohoka, H., additional, Osone, S., additional, Sakaki, N., additional, Sakurai, N., additional, Sasaki, M., additional, Sasano, M., additional, Takeda, M., additional, Teshima, M., additional, Tsushima, I., additional, Torii, R., additional, Uchihori, Y., additional, Vázquez, R. A., additional, Yamamoto, T., additional, Yoshida, S., additional, and Yoshii, H., additional

Published
2002
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41. Simultaneous observation of families and accompanied air showers at Mt. Chacaltaya. II. Study of the hadronic component in air showers

Author

Aguirre, C., primary, Aoki, H., additional, Hashimoto, K., additional, Honda, K., additional, Inoue, N., additional, Kawasumi, N., additional, Maeda, Y., additional, Martinic, N., additional, Matano, T., additional, Ohmori, N., additional, Ohsawa, A., additional, Shinozaki, K., additional, Tamada, M., additional, Ticona, R., additional, and Tsushima, I., additional

Published
2000
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42. Small‐Scale Anisotropy of Cosmic Rays above 1019eV Observed with the Akeno Giant Air Shower Array

Author

Takeda, M., primary, Hayashida, N., additional, Honda, K., additional, Inoue, N., additional, Kadota, K., additional, Kakimoto, F., additional, Kamata, K., additional, Kawaguchi, S., additional, Kawasaki, Y., additional, Kawasumi, N., additional, Kusano, E., additional, Matsubara, Y., additional, Murakami, K., additional, Nagano, M., additional, Nishikawa, D., additional, Ohoka, H., additional, Osone, S., additional, Sakaki, N., additional, Sasaki, M., additional, Shinozaki, K., additional, Souma, N., additional, Teshima, M., additional, Torii, R., additional, Tsushima, I., additional, Uchihori, Y., additional, Yamamoto, T., additional, Yoshida, S., additional, and Yoshii, H., additional

Published
1999
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43. Observations of T[CLC]e[/CLC]V Gamma-Ray Flares from Markarian 501with the Telescope Array Prototype

Author

Hayashida, N., primary, Hirasawa, H., additional, Ishikawa, F., additional, Lafoux, H., additional, Nagano, M., additional, Nishikawa, D., additional, Ouchi, T., additional, Ohoka, H., additional, Ohnishi, M., additional, Sakaki, N., additional, Sasaki, M., additional, Shimodaira, H., additional, Teshima, M., additional, Torii, R., additional, Yamamoto, T., additional, Yoshida, S., additional, Yuda, T., additional, Hayashi, Y., additional, Ito, N., additional, Kawakami, S., additional, Kawasaki, Y., additional, Matsuyama, T., additional, Sasano, M., additional, Takahashi, T., additional, Chamoto, N., additional, Kajino, F., additional, Sakata, M., additional, Sugiyama, T., additional, Tsukiji, M., additional, Yamamoto, Y., additional, Inoue, N., additional, Kusano, E., additional, Mizutani, K., additional, Shiomi, A., additional, Hibino, K., additional, Kashiwagi, T., additional, Nishimura, J., additional, Loh, E. C., additional, Sokolsky, P., additional, Taylor, S. F., additional, Honda, K., additional, Kawasumi, N., additional, Tsushima, I., additional, Uchihori, Y., additional, Kitamura, H., additional, Chikawa, M., additional, Kabe, S., additional, Mizumoto, Y., additional, Yoshii, H., additional, Hotta, N., additional, Saito, To., additional, Nishizawa, M., additional, Kuramochi, H., additional, and Sakumoto, K., additional

Published
1998
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44. Extension of the Cosmic-Ray Energy Spectrum beyond the Predicted Greisen-Zatsepin-Kuz'min Cutoff

Author

Takeda, M., primary, Hayashida, N., additional, Honda, K., additional, Inoue, N., additional, Kadota, K., additional, Kakimoto, F., additional, Kamata, K., additional, Kawaguchi, S., additional, Kawasaki, Y., additional, Kawasumi, N., additional, Kitamura, H., additional, Kusano, E., additional, Matsubara, Y., additional, Murakami, K., additional, Nagano, M., additional, Nishikawa, D., additional, Ohoka, H., additional, Sakaki, N., additional, Sasaki, M., additional, Shinozaki, K., additional, Souma, N., additional, Teshima, M., additional, Torii, R., additional, Tsushima, I., additional, Uchihori, Y., additional, Yamamoto, T., additional, Yoshida, S., additional, and Yoshii, H., additional

Published
1998
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47. Simultaneous observation of families and accompanied air showers at Mt. Chacaltaya I

Author

Honda, K., primary, Kawasumi, N., additional, Tsushima, I., additional, Hashimoto, K., additional, Nishida, T., additional, Matano, T., additional, Inoue, N., additional, Ohsawa, A., additional, Tamada, M., additional, Ohmori, N., additional, Martinic, N., additional, Ticona, R., additional, Gironda, N., additional, Osco, F., additional, and Aguirre, C., additional

Published
1997
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48. Study of primary cosmic ray composition from gamma ray families in air shower cores

Author

Honda, K., primary, Kawasumi, N., additional, Tsushima, I., additional, Hashimoto, K., additional, Nishida, T., additional, Matano, T., additional, Inoue, N., additional, Ohsawa, A., additional, Tamada, M., additional, Ohmori, N., additional, Martinic, N., additional, Ticona, R., additional, Gironda, N., additional, Osco, F., additional, and Aguirre, C., additional

Published
1997
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49. Further development of data acquisition system of the Akeno Giant Air Shower Array

Author

Ohoka, H., primary, Takeda, M., additional, Hayashida, N., additional, Honda, K., additional, Honda, M., additional, Inoue, N., additional, Kadota, K., additional, Kakimoto, F., additional, Kamata, K., additional, Kawaguchi, S., additional, Kawasumi, N., additional, Matsubara, Y., additional, Murakami, K., additional, Nagano, M., additional, Teshima, M., additional, Tsushima, I., additional, Uchihori, Y., additional, Yoshida, S., additional, and Yoshii, H., additional

Published
1997
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50. Possible Clustering of the Most Energetic Cosmic Rays within a Limited Space Angle Observed by the Akeno Giant Air Shower Array

Author

Hayashida, N., primary, Honda, K., additional, Honda, M., additional, Inoue, N., additional, Kadota, K., additional, Kakimoto, F., additional, Kamata, K., additional, Kawaguchi, S., additional, Kawasumi, N., additional, Matsubara, Y., additional, Murakami, K., additional, Nagano, M., additional, Ohoka, H., additional, Sakaki, N., additional, Souma, N., additional, Takeda, M., additional, Teshima, M., additional, Tsushima, I., additional, Uchihori, Y., additional, Yoshida, S., additional, and Yoshii, H., additional

Published
1996
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