1997 Fiscal Year Final Research Report Summary
Survey of Transient Radio Sources with Digital Interferome
| Project/Area Number |
06405008
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
広領域
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| Research Institution | Waseda University |
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Principal Investigator |
KOMATSU Shinichi Waseda University, Dep. Science & Engineering, Professor, 理工学部, 教授 (00087446)
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| Co-Investigator(Kenkyū-buntansha) |
OHBA Ichiro 早稲田大学, 理工学部, 教授 (10063695)
AIZAWA Yohji 早稲田大学, 理工学部, 教授 (70088855)
OHARA Hirayoshi 早稲田大学・理工学部 (40063367)
YAMADA Masami Waseda University, Dep. Science & Engineering, Professor, 理工学総合研究センター, 名誉教授 (30063316)
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| Project Period (FY) |
1994 – 1997
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| Keywords | Interterometer / FFT / Transient Radio Source / Nyquist rate / Engodicity |
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| Research Abstract |
64 element radio interferometer developed for these six years has achieved three times higher sensitivity than before with new HEMT receivers. It is monitoring transient radio sources like Cyg X-3, and watching gamma-ray quasars and rapidly varying BL Lac objects. The interferometer has made it possible to get radio images at Nyquist rate for the first time in the world.
All radio interferometers currently used in the world are Fourier synthesis (indirect imaging interferometer), which could make fine radio maps. The method developed by Cambridge University is optimized to get fine images with less number of antenas, using Wiener-Khinchin theorem. It requires ergodicity(time average = ensamble mean) in received signals.
Since signals from the astronomical radio sources usually do not change rapidly, and the ergodicity is satisfied. However signals from pulsars or comunication are non-ergodic, so Fourier synthesis is inapropiate to search pulsars.
Direct imaging interferometer developed by Waseda University transforms the spatially received waves to the directional amplitudes using spatial FFT processing, in which cordinate representation is related to momentum representation by Fourier transform. Comunication signals could also be processed by this processor, and it is usefull in the fields of simultaneous and multi-directionai comunications. We have got a patent of the procesor.
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[Publications] Otobe, E., Nakajima, J., Nishibori, K., Saito, T., Kobayashi, H., Tanaka, N., Watanabe, N., Aramaki, Y., Hoshikawa, T., Asuma, K., and Daishido, T: "Two-Dimentional Direct images with Spatial FFT Interferometer"Publ. Astron. Soc. Japan. Vol. 46. 503-510 (1994)
Description
「研究成果報告書概要(欧文)」より
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[Publications] Kobayashi, H., Asuma, K., Nishibori, K., Nakajima, J., Otobe, E., Watanabe, Aramaki, Y., N., Saito, T., Tanaka, N., Hoshikawa, T., Takagi, M., Kimoto, D., and Daishido, T.: "Radio Observation of AGN by the 64-Element Dgital Interferometer"Proc. "New Horizon of X-Ray Astronomy, First Results from ASCA" 1994, Universal Academy Press. 651-652
Description
「研究成果報告書概要(欧文)」より
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[Publications] Tanaka, N., Otobe, E., Kobayashi, H., Saito, T., Takagi, M., Aramaki, Y., Kimoto, D., and Daishido, T.: "Scanning Galactic Plane by the Multi Directional Finding Radio interferometer"Proc. "New Horizon of X-Ray Astronomy, First Results from ASCA" 1994, Universal Academy Press. 661-662
Description
「研究成果報告書概要(欧文)」より
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[Publications] Otobe, E., Nakajima, J., Nishibori, K., Asuma, K., Saito, T., Kobayashi, H., Tanaka, N., Watanabe, N., Aramaki, Y., Takagi, M., Sudo, S., Hoshikawa, T., Suzuki, M., and Daishido, T.: "Phase Calibration for Two-Dimentional Direct Imaging Observation in a Waseda Spatial FFT Interferometer"Proc. "Scientific and Engineering Frontiers for 8-10m Telescopes" 1995, Universal Academy Press. 397-402
Description
「研究成果報告書概要(欧文)」より
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[Publications] Daishido, T., Tanaka, N., Sudo, S., Suzuki, M., Saito, Y., Agehama, R., Adachi, M. and Watanabe, N.: "Design of (2+1+2)D FFT for Interferometric Pulsar Survey"Proc. "PULSARS : PROBLEMS AND PROGRESS", 1996, APS Conference Series. 105. 19-20
Description
「研究成果報告書概要(欧文)」より
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[Publications] Tanaka, N., Sudo, S., Saito, Y., Suzuki, M., Adachi, M., Takeuchi, H., Naritsuka, T., Daishido, T., and iwase, S.: "Design of Radix-4 FFT Based Butterfly LSI"Proc. TWAA96-Kashima/CRL. 274-278 (1996)
Description
「研究成果報告書概要(欧文)」より
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[Publications] Takeuchi, H., Tanaka, N., Sudo, S., Saito, Y., Suzuki, M., Adachi, M., T., Daishido, T., and Watanabe, N.: "2 24 Point Floating FFT Processor Design for Real Time Pulsar Survey"Proc. TWAA96-Kashima/CRL. 279-283 (1996)
Description
「研究成果報告書概要(欧文)」より
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[Publications] Daishido, T., Tanaka, N., Takeuchi, H., Adachi, M., Oura, S., and Fujii: "(2+1+2)D Signal Processing in Pulsar Survey Project"Proc. "Neutron Stars and Pulsars, Thirty Years after the Dicovery" 1997, Universal Academy Press. 233-234
Description
「研究成果報告書概要(欧文)」より
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[Publications] Tanaka, N., Agehama, R., Sudo, S., Saito, Y., Suzuki, M., Adachi, M., and Daishido, T.: "Control Softwares Using C++ in Waseda 8x8 FFT Radio Interferometer"Proc. "X-Ray Imaging and Spectroscopy of Cosmic Hot Plasmas" 1997, Universal Academy Press. 627-628
Description
「研究成果報告書概要(欧文)」より
