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Akihiro DOI

  (土居 明広)

Profile Information

Affiliation
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency
School of Physical Sciences Department of Space and Astronautical Science, The Graduate University for Advanced Studies
Degree
博士 (理学)(Mar, 2005, 東京大学)
Researcher number
90403641
ORCID ID
 https://orcid.org/0000-0003-4384-9568
J-GLOBAL ID
201101033666007265
researchmap Member ID
B000004312

Research Interests

 11

Research Areas

 3

Research History

 3

Papers

 118
  • Kazunori Akiyama, Kotaro Niinuma, Kazuhiro Hada, Akihiro Doi, Yoshiaki Hagiwara, Aya Higuchi, Mareki Honma, Tomohisa Kawashima, Dimitar Kolev, Shoko Koyama, Sho Masui, Ken Ohsuga, Hidetoshi Sano, Hideki Takami, Yuh Tsunetoe, Yoshinori Uzawa, Takuya Akahori, Yuto Akiyama, Peter Galison, Takayuki J. Hayashi, Tomoya Hirota, Makoto Inoue, Yuhei Iwata, Michael Johnson, Motoki Kino, Yutaro Kofuji, Yosuke Mizuno, Kotaro Moriyama, Hiroshi Nagai, Kenta Nakamura, Shota Notsu, Fumie Ono, Yoko Oya, Tomoaki Oyama, Hannah Rana, Hiromi Saida, Ryo Saito, Yoshihiko Saito, Mahito Sasada, Satoko Sawada-Satoh, Mikiya M. Takahashi, Mieko Takamura, Edward Tong, Hiroyuki Tsuji, Shogo Yoshioka, Yoshimasa Watanabe
    Space Telescopes and Instrumentation 2024: Optical, Infrared, and Millimeter Wave, 91-91, Aug 23, 2024  
  • Kohji Tsumura, Hideo Matsuhara, Koji S. Kawabata, Hiroshi Akitaya, Shuji Matsuura, Haruki Fukui, Akihiro Miyasaka, Keisuke Shinozaki, Akihiro Doi, Daisuke Yonetoku
    Space Telescopes and Instrumentation 2024: Optical, Infrared, and Millimeter Wave, 86-86, Aug 23, 2024  
  • Koji S. Kawabata, Kohji Tsumura, Daisuke Yonetoku, Hideo Matsuhara, Shuji Matsuura, Akihiro Doi, Hiroshi Akitaya, Tomoya Hori
    Space Telescopes and Instrumentation 2024: Optical, Infrared, and Millimeter Wave, 203-203, Aug 23, 2024  
  • Daisuke Yonetoku, Akihiro Doi, Tatehiro Mihara, Hideo Matsuhara, Takanori Sakamoto, Kohji Tsumura, Kunihito Ioka, Makoto Arimoto, Teruaki Enoto, Kenjiro Fujimoto, Hatsune Goto, Shuichi Gunji, Junko S. Hiraga, Shintaro Ikunaga, Nobuyuki Kawai, Ryuji Kondo, Shunsuke Kurosawa, Junyi Li, Yoshitomo Maeda, Ikuyuki Mitsuishi, Toshio Murakami, Issin Nagataka, Yujin Nakagawa, Naoki Ogino, Taiki Owari, Ryuji Sato, Masataka Sato, Tomoya Sato, Tatsuya Sawano, Motoko Serino, Hsien-Chieh Shen, Satoshi Sugita, Shuta Takahashi, Toru Tamagawa, Keisuke Tamura, Takaaki Tanaka, Toru Tanimori, Makoto S. Tashiro, Takumi Togashi, Hiroshi Tomida, Keito Watanabe, Kazutaka Yamaoka, Makoto Yamauchi, Yoichi Yatsu, Atsumasa Yoshida, Hiroshi Akitaya, Akihiko Fukui, Haruki Fukui, Yoshifusa Ita, Koji Kawabata, Shuji Matsuura, Akihiro Miyasaka, Kentaro Motohara, Norio Narita, Hirofumi Noda, Hirofumi Okita, Kei Sano, Keisuke Shinozaki, Sou Tajima, Yuji Urata, Takehiko Wada, Kenshi Yanagisawa, Michitoshi Yoshida, Nobutaka Bando, Ichiro Jikuya, Kenji Minesugi, Yasuyuki Miyazaki, Yusuke Kono, Naoki Takase, Shunichi Nakatsubo, Tooru Kaga, Katsuaki Asano, Kohei Inayoshi, Susumu Inoue, Hirotaka Ito, Hideyuki Izumiura, Norita Kawanaka, Tomoya Kinugawa, Shota Kisaka, Kenta Kiuchi, Kotaro Kyutoku, Jin Matsumoto, Akira Mizuta, Kohta Murase, Hiroki Nagakura, Shigehiro Nagataki, Yoshikazu Nakada, Takashi Nakamura, Yuu Niino, Yudai Suwa, Keitaro Takahashi, Takahiro Tanaka, Kenji Toma, Tomonori Totani, Ryo Yamazaki, Jun'ichi Yokoyama, Yuichi Harikane, Masaomi Tanaka, Shigeo Kimura, Mariko Kimura
    Space Telescopes and Instrumentation 2024: Ultraviolet to Gamma Ray, 75-75, Aug 21, 2024  
  • Shuta Takahashi, Makoto Arimoto, Hatsune Goto, Ryuji Kondo, Daisuke Yonetoku, Robert Hartmann, Lothar Strueder, Peter Holl, Naoki Ogino, Tatsuya Sawano, Junko Hiraga, Masataka Sato, Takanori Sakamoto, Hsien-Chieh Shen, Satoshi Hatori, Ryoya Ishigami, Akihiro Doi, Hideo Matsuhara
    NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 1064, Jul, 2024  Peer-reviewed
  • Takayuki J Hayashi, Akihiro Doi, Hiroshi Nagai
    Monthly Notices of the Royal Astronomical Society, 530(3) 2590-2607, Apr 15, 2024  Peer-reviewed
    ABSTRACT A substantial fraction of quasars display broad absorption lines (BALs) in their rest-frame ultraviolet spectra. While the origin of BALs is thought to be related to the accretion disc wind, it remains unclear whether the observed ratio of BAL to non-BAL quasars is a result of orientation. We conducted observations of 48 BAL quasars and the same number of non-BAL quasars at 322 MHz using the Giant Metrewave Radio Telescope. Combined with previous flux measurements ranging from MHz to GHz frequencies, we compared continuum radio spectra between the two quasar groups. These data offer insights into low-frequency radio properties that have been difficult to investigate with previous observations only at GHz frequencies. Our results show that 73 ± 13 per cent of the BAL quasars exhibit steep or peaked spectra, a higher proportion than the 44 ± 14 per cent observed in the non-BAL quasars. In contrast, there are no discernible differences between the two quasar groups in the radio luminosity, peak frequency, and spectral index distributions of sources with steep or peaked spectra and sources with flat or inverted spectra. Generally, as the jet axis and line of sight become closer to parallel, quasars exhibit flat or inverted spectra rather than steep or peaked spectra. Therefore, these results suggest that BAL quasars are more frequently observed farther from the jet axis than non-BAL quasars. However, given that a certain proportion of BAL quasars exhibit flat or inverted spectra, more than the simple orientation scenario is required to elucidate the radio properties of BAL quasars.
  • Enrico Bozzo, Lorenzo Amati, Wayne Baumgartner, Tzu-Ching Chang, Bertrand Cordier, Nicolas De Angelis, Akihiro Doi, Marco Feroci, Cynthia Froning, Jessica Gaskin, Adam Goldstein, Diego Goetz, Jon E. Grove, Sylvain Guiriec, Margarita Hernanz, C. Michelle Hui, Peter Jenke, Daniel Kocevski, Merlin Kole, Chryssa Kouveliotou, Thomas Maccarone, Mark L. Mcconnell, Hideo Matsuhara, Paul O'Brien, Nicolas Produit, Paul S. Ray, Peter Roming, Andrea Santangelo, Michael Seiffert, Hui Sun, Alexander van der Horst, Peter Veres, Jianyan Wei, Nicholas White, Colleen Wilson-Hodge, Daisuke Yonetoku, Weimin Yuan, Shuang-Nan Zhang
    UNIVERSE, 10(4), Apr, 2024  Peer-reviewed
  • Tomonari Michiyama, Yoshiyuki Inoue, Akihiro Doi, Tomoya Yamada, Yasushi Fukazawa, Hidetoshi Kubo, Samuel Barnier
    The Astrophysical Journal, 965(1) 68-68, Apr 1, 2024  Peer-reviewed
  • Hiroaki TANAKA, Takashi IWASA, Nozomu KOGISO, Nobuhisa KATSUMATA, Hiraku SAKAMOTO, Tadashige IKEDA, Naoko KISHIMOTO, Ken HIGUCHI, Motoharu FUJIGAKI, Akihiro DOI, Yasutaka SATO, Masahiro YAMATANI
    JAXA Research and Development Report, 23(003) 1-21, Feb, 2024  Peer-reviewed
  • Takumi Togashi, Shuichi Gunji, Ryuji Sato, Keito Watanabe, Haruaki Niinuma, Daisuke Yonetoku, Hiroshi Akitaya, Akihiro Doi, Hatsune Goto, Yusuke Kono, Hideo Matsuhara, Tatehiro Mihara, Takanori Sakamoto, Tatsuya Sawano
    SPACE TELESCOPES AND INSTRUMENTATION 2024: ULTRAVIOLET TO GAMMA RAY, PT 1, 13093, 2024  
  • Takanori Sakamoto, Daisuke Yonetoku, Akihiro Doi, Hideo Matsuhara, Tatehiro Mihara, Makoto Arimoto, Tatsuya Sawano, Shuichi Gunji, Junko Hiraga
    SPACE TELESCOPES AND INSTRUMENTATION 2024: ULTRAVIOLET TO GAMMA RAY, PT 1, 13093, 2024  
  • Hatsune Goto, Daisuke Yonetoku, Makoto Arimoto, Tatsuya Sawano, Isshin Nagataka, Takanori Sakamoto, Tatehiro Mihara, Takumi Togashi, Akihiro Doi, Yoshitomo Maeda, Hideo Matsuhara, Naoki Takase, Toru Kagae, Shunichi Nakatsubo
    SPACE TELESCOPES AND INSTRUMENTATION 2024: ULTRAVIOLET TO GAMMA RAY, PT 1, 13093, 2024  
  • Tomonari Michiyama, Yoshiyuki Inoue, Akihiro Doi
    Publications of the Astronomical Society of Japan, Oct 3, 2023  Peer-reviewed
  • Mieko Takamura, Kazuhiro Hada, Mareki Honma, Tomoaki Oyama, Aya Yamauchi, Syunsaku Suzuki, Yoshiaki Hagiwara, Monica Orienti, Filippo D’Ammando, Jongho Park, Minchul Kam, Akihiro Doi
    The Astrophysical Journal, Jul 1, 2023  Peer-reviewed
  • Ru-Sen Lu, Keiichi Asada, Thomas P. Krichbaum, Jongho Park, Fumie Tazaki, Hung-Yi Pu, Masanori Nakamura, Andrei Lobanov, Kazuhiro Hada, Kazunori Akiyama, Jae-Young Kim, Ivan Marti-Vidal, José L. Gómez, Tomohisa Kawashima, Feng Yuan, Eduardo Ros, Walter Alef, Silke Britzen, Michael Bremer, Avery E. Broderick, Akihiro Doi, Gabriele Giovannini, Marcello Giroletti, Paul T. P. Ho, Mareki Honma, David H. Hughes, Makoto Inoue, Wu Jiang, Motoki Kino, Shoko Koyama, Michael Lindqvist, Jun Liu, Alan P. Marscher, Satoki Matsushita, Hiroshi Nagai, Helge Rottmann, Tuomas Savolainen, Karl-Friedrich Schuster, Zhi-Qiang Shen, Pablo de Vicente, R. Craig Walker, Hai Yang, J. Anton Zensus, Juan Carlos Algaba, Alexander Allardi, Uwe Bach, Ryan Berthold, Dan Bintley, Do-Young Byun, Carolina Casadio, Shu-Hao Chang, Chih-Cheng Chang, Song-Chu Chang, Chung-Chen Chen, Ming-Tang Chen, Ryan Chilson, Tim C. Chuter, John Conway, Geoffrey B. Crew, Jessica T. Dempsey, Sven Dornbusch, Aaron Faber, Per Friberg, Javier González García, Miguel Gómez Garrido, Chih-Chiang Han, Kuo-Chang Han, Yutaka Hasegawa, Ruben Herrero-Illana, Yau-De Huang, Chih-Wei L. Huang, Violette Impellizzeri, Homin Jiang, Hao Jinchi, Taehyun Jung, Juha Kallunki, Petri Kirves, Kimihiro Kimura, Jun Yi Koay, Patrick M. Koch, Carsten Kramer, Alex Kraus, Derek Kubo, Cheng-Yu Kuo, Chao-Te Li, Lupin Chun-Che Lin, Ching-Tang Liu, Kuan-Yu Liu, Wen-Ping Lo, Li-Ming Lu, Nicholas MacDonald, Pierre Martin-Cocher, Hugo Messias, Zheng Meyer-Zhao, Anthony Minter, Dhanya G. Nair, Hiroaki Nishioka, Timothy J. Norton, George Nystrom, Hideo Ogawa, Peter Oshiro, Nimesh A. Patel, Ue-Li Pen, Yurii Pidopryhora, Nicolas Pradel, Philippe A. Raffin, Ramprasad Rao, Ignacio Ruiz, Salvador Sanchez, Paul Shaw, William Snow, T. K. Sridharan, Ranjani Srinivasan, Belén Tercero, Pablo Torne, Efthalia Traianou, Jan Wagner, Craig Walther, Ta-Shun Wei, Jun Yang, Chen-Yu Yu
    Nature, 616(7958) 686-690, Apr 26, 2023  Peer-reviewed
    Abstract The nearby radio galaxy M87 is a prime target for studying black hole accretion and jet formation1,2. Event Horizon Telescope observations of M87 in 2017, at a wavelength of 1.3 mm, revealed a ring-like structure, which was interpreted as gravitationally lensed emission around a central black hole3. Here we report images of M87 obtained in 2018, at a wavelength of 3.5 mm, showing that the compact radio core is spatially resolved. High-resolution imaging shows a ring-like structure of $${8.4}_{-1.1}^{+0.5}$$ Schwarzschild radii in diameter, approximately 50% larger than that seen at 1.3 mm. The outer edge at 3.5 mm is also larger than that at 1.3 mm. This larger and thicker ring indicates a substantial contribution from the accretion flow with absorption effects, in addition to the gravitationally lensed ring-like emission. The images show that the edge-brightened jet connects to the accretion flow of the black hole. Close to the black hole, the emission profile of the jet-launching region is wider than the expected profile of a black-hole-driven jet, suggesting the possible presence of a wind associated with the accretion flow.
  • Gabriele Giovannini, Yuzhu Cui, Kazuhiro Hada, Kunwoo Yi, Hyunwook Ro, Bong Won Sohn, Mieko Takamura, Salvatore Buttaccio, Filippo D’Ammando, Marcello Giroletti, Yoshiaki Hagiwara, Motoki Kino, Evgeniya Kravchenko, Giuseppe Maccaferri, Alexey Melnikov, Kotaro Niinuma, Monica Orienti, Kiyoaki Wajima, Kazunori Akiyama, Akihiro Doi, Do-Young Byun, Tomoya Hirota, Mareki Honma, Taehyun Jung, Hideyuki Kobayashi, Shoko Koyama, Andrea Melis, Carlo Migoni, Yasuhiro Murata, Hiroshi Nagai, Satoko Sawada-Satoh, Matteo Stagni
    Galaxies, 11(2) 49-49, Mar 22, 2023  Peer-reviewed
    We present here the East Asia to Italy Nearly Global VLBI (EATING VLBI) project. How this project started and the evolution of the international collaboration between Korean, Japanese, and Italian researchers to study compact sources with VLBI observations is reported. Problems related to the synchronization of the very different arrays and technical details of the telescopes involved are presented and discussed. The relatively high observation frequency (22 and 43 GHz) and the long baselines between Italy and East Asia produced high-resolution images. We present example images to demonstrate the typical performance of the EATING VLBI array. The results attracted international researchers and the collaboration is growing, now including Chinese and Russian stations. New in progress projects are discussed and future possibilities with a larger number of telescopes and a better frequency coverage are briefly discussed herein.
  • Kazunori Akiyama, Juan-Carlos Algaba, Tao An, Keiichi Asada, Kitiyanee Asanok, Do-Young Byun, Thanapol Chanapote, Wen Chen, Zhong Chen, Xiaopeng Cheng, James O. Chibueze, Ilje Cho, Se-Hyung Cho, Hyun-Soo Chung, Lang Cui, Yuzhu Cui, Akihiro Doi, Jian Dong, Kenta Fujisawa, Wei Gou, Wen Guo, Kazuhiro Hada, Yoshiaki Hagiwara, Tomoya Hirota, Jeffrey A. Hodgson, Mareki Honma, Hiroshi Imai, Phrudth Jaroenjittichai, Wu Jiang, Yongbin Jiang, Yongchen Jiang, Takaaki Jike, Dong-Kyu Jung, Taehyun Jung, Noriyuki Kawaguchi, Dong-Jin Kim, Hyo-Ryoung Kim, Jaeheon Kim, Jeong-Sook Kim, Kee-Tae Kim, Soon-Wook Kim, Motoki Kino, Hideyuki Kobayashi, Shoko Koyama, Busaba H. Kramer, Jee-Won Lee, Jeong Ae Lee, Sang-Sung Lee, Sang Won Lee, Bin Li, Guanghui Li, Xiaofei Li, Zhixuan Li, Qinghui Liu, Xiang Liu, Ru-Sen Lu, Kazuhito Motogi, Masanori Nakamura, Kotaro Niinuma, Chungsik Oh, Hongjong Oh, Junghwan Oh, Se-Jin Oh, Tomoaki Oyama, Jongho Park, Saran Poshyachinda, Hyunwook Ro, Duk-Gyoo Roh, Wiphu Rujopakarn, Nobuyuki Sakai, Satoko Sawada-Satoh, Zhi-Qiang Shen, Katsunori M. Shibata, Bong Won Sohn, Boonrucksar Soonthornthum, Koichiro Sugiyama, Yunxia Sun, Mieko Takamura, Yoshihiro Tanabe, Fumie Tazaki, Sascha Trippe, Kiyoaki Wajima, Jinqing Wang, Na Wang, Shiqiang Wang, Xuezheng Wang, Bo Xia, Shuangjing Xu, Hao Yan, Wenjun Yang, Jae-Hwan Yeom, Kunwoo Yi, Sang-Oh Yi, Yoshinori Yonekura, Hasu Yoon, Linfeng Yu, Jianping Yuan, Youngjoo Yun, Bo Zhang, Hua Zhang, Yingkang Zhang, Guang-Yao Zhao, Rongbing Zhao, Weiye Zhong
    Galaxies, 10(6) 113-113, Dec 7, 2022  Peer-reviewed
    The East Asian VLBI Network (EAVN) is an international VLBI facility in East Asia and is operated under mutual collaboration between East Asian countries, as well as part of Southeast Asian and European countries. EAVN currently consists of 16 radio telescopes and three correlators located in China, Japan, and Korea, and is operated mainly at three frequency bands, 6.7, 22, and 43 GHz with the longest baseline length of 5078 km, resulting in the highest angular resolution of 0.28 milliarcseconds at 43 GHz. One of distinct capabilities of EAVN is multi-frequency simultaneous data reception at nine telescopes, which enable us to employ the frequency phase transfer technique to obtain better sensitivity at higher observing frequencies. EAVN started its open-use program in the second half of 2018, providing a total observing time of more than 1100 h in a year. EAVN fills geographical gap in global VLBI array, resulting in enabling us to conduct contiguous high-resolution VLBI observations. EAVN has produced various scientific accomplishments especially in observations toward active galactic nuclei, evolved stars, and star-forming regions. These activities motivate us to initiate launch of the ’Global VLBI Alliance’ to provide an opportunity of VLBI observation with the longest baselines on the earth.
  • Tomonari Michiyama, Yoshiyuki Inoue, Akihiro Doi, Dmitry Khangulyan
    The Astrophysical Journal Letters, 936(1) L1-L1, Aug 17, 2022  Peer-reviewed
    We present Atacama Large Millimeter/submillimeter Array observations at $\approx100$ GHz with $0.05$ arcsec (3 pc) resolution of the kiloparsec-scale jet seen in the nearby Seyfert galaxy NGC 1068, and we report the presence of parsec-scale blobs at the head of the jet. The combination of the detected radio flux ($\approx0.8$ mJy), spectral index ($\approx0.5$), and the blob size ($\approx10$ pc) suggests a strong magnetic field of $B\approx240\,\mu$G. Such a strong magnetic field most likely implies magnetic field amplification by streaming cosmic rays. The estimated cosmic-ray power by the jet may exceed the limit set by the star formation activity in this galaxy. This result suggests that even modest-power jets can increase the galactic cosmic-ray content while propagating through the galactic bulge.
  • Tomonari Michiyama, Yoshiyuki Inoue, Akihiro Doi, Dmitry Khangulyan
    Research Square, Mar 28, 2022  
  • ISHIMURA Kosei, KAWANO Taro, TORISAKA Ayako, MIYASHITA Tomoyuki, DOI Akihiro, YAMAZAKI Maho, YASUDA Yuya, TANAKA Hiroaki, KOGISO Nozomu, NAKAO Tatsuro, TAMURA Makoto, MIZUMURA Yoshitaka, FUKE Hideyuki, OBATA Souma, YAMAMOTO Koya
    JAXA Research and Development Report, 21-003 35-49, Feb 18, 2022  Peer-reviewed
  • iroaki Tanaka, Nozomu Kogiso, Fumika Sakano, Nobuhisa Katsumata, Kenji Yamazaki, Ken Higuchi, Kosei Ishimura, Takashi Iwasa, Naoko Kishimoto, Motoharu Fujigaki, Akihiro Doi, Satomi Nakahara, Yutaka Hasegawa, Yusuke Kono
    Acta Astronautica, 194 93-105, Feb, 2022  Peer-reviewed
  • Koichi Yokota, Nozomu Kogiso, Kisumi Iida, Akihiro Doi
    Journal of the Japan Society for Aeronautical and Space Sciences, 70(2), 2022  Peer-reviewed
  • Yoshiyuki Inoue, Dmitry Khangulyan, Akihiro Doi
    GALAXIES, 9(2), Jun, 2021  
  • Akihiro Doi, Yusuke Kono, Kazuyoshi YAMASHITA, Yasutaka SATOU
    JAXA Research and Development Report, 20(009) 57-67, Feb 26, 2021  Peer-reviewedLead author
  • Ryosuke Itoh, Yousuke Utsumi, Yoshiyuki Inoue, Kouji Ohta, Akihiro Doi, Tomoki Morokuma, Koji S. Kawabata, Yasuyuki T. Tanaka
    The Astrophysical Journal, 901(1) 3-3, Sep 16, 2020  Peer-reviewed
  • Akihiro Doi, Yusuke Kono, Kimihiro Kimura, Satomi Nakahara, Tomoaki Oyama, Nozomi Okada, Yasutaka Satou, Kazuyoshi Yamashita, Naoko Matsumoto, Mitsuhisa Baba, Daisuke Yasuda, Shunsaku Suzuki, Yutaka Hasegawa, Mareki Honma, Hiroaki Tanaka, Kosei Ishimura, Yasuhiro Murata, Reiho Shimomukai, Tomohiro Tachi, Kazuya Saito, Naohiko Watanabe, Nobutaka Bando, Osamu Kameya, Yoshinori Yonekura, Mamoru Sekido, Yoshiyuki Inoue, Hiraku Sakamoto, Nozomu Kogiso, Yasuhiro Shoji, Hideo Ogawa, Kenta Fujisawa, Masanao Narita, Hiroshi Shibai, Hideyuki Fuke, Kenta Uehara, Shoko Koyama
    Advances in Space Research, 66(3) 751-752, Aug 1, 2020  
  • Akihiro Doi, Motoki Kino, Nozomu Kawakatu, Kazuhiro Hada
    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 496(2) 1757-1765, Aug, 2020  Peer-reviewedLead author
  • Yoshiyuki Inoue, Dmitry Khangulyan, Akihiro Doi
    The Astrophysical Journal, 891(2) L33-L33, Mar 9, 2020  Peer-reviewed
  • Satomi Nakahara, Akihiro Doi, Yasuhiro Murata, Masanori Nakamura, Kazuhiro Hada, Keiichi Asada, Satoko Sawada-Satoh, Seiji Kameno
    ASTRONOMICAL JOURNAL, 159(1), Jan, 2020  Peer-reviewed
  • Shoko Koyama, Motoki Kino, Akihiro Doi, Kotaro Niinuma, Marcello Giroletti, David Paneque, Kazunori Akiyama, Gabriele Giovannini, Guang-Yao Zhao, Eduardo Ros, Jun Kataoka, Monica Orienti, Kazuhiro Hada, Hiroshi Nagai, Naoki Isobe, Hideyuki Kobayashi, Mareki Honma, Rocco Lico
    ASTROPHYSICAL JOURNAL, 884(2) 132, Oct, 2019  Peer-reviewed
  • Yoshiyuki Inoue, Dmitry Khangulyan, Susumu Inoue, Akihiro Doi
    ASTROPHYSICAL JOURNAL, 880(1) 40-40, Jul, 2019  Peer-reviewed
  • Akihiro Doi, Satomi Nakahara, Masanori Nakamura, Motoki Kino, Nozomu Kawakatu, Hiroshi Nagai
    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 487(1) 640-649, Jul, 2019  Peer-reviewedLead author
  • Satomi Nakahara, Akihiro Doi, Yasuhiro Murata, Masanori Nakamura, Kazuhiro Hada, Keiichi Asada
    ASTROPHYSICAL JOURNAL, 878(1) 61-61, Jun, 2019  Peer-reviewedCorresponding author
  • ISHIMURA Kosei, KOGISO Nozomu, KAWANO Taro, TORISAKA Ayako, DOI Akihiro, FUKE Hideyuki, TAMURA Makoto, MIYASHITA Tomoyuki, YAMAZAKI Maho, TANAKA Hiroaki
    The Proceedings of Mechanical Engineering Congress, Japan, 2019 F19101, 2019  
    <p>For future advanced missions, large and highly accurate space structures are required. A prior shape adjustment of the structure before launch is not sufficient to achieve such accurate space structures. For example, thermal deformation on orbit cannot be eliminated by the preliminary adjustment of the structure. Therefore, the shape control of the structure is a promising technique for highly accurate space structures. For the shape control, the shape error should be measured on-orbit. In this study, a measurement system for the displacement of a slender space structure has been developed as an alignment monitor. The characteristics of this measurement system are long working distance and simple configuration. The measurement system consists of a laser, retro-reflector and positioning sensing device. The performance on the ground was already demonstrated through the satellite ground test. As a first step to on-orbit experiment, the demonstration experiment on the balloon is planned. In this paper, the system configuration and development progress are reported.</p>
  • Akihiro Doi, Yusuke Kono, Kimihiro Kimura, Satomi Nakahara, Tomoaki Oyama, Nozomi Okada, Yasutaka Satou, Kazuyoshi Yamashita, Naoko Matsumoto, Mitsuhisa Baba, Daisuke Yasuda, Shunsaku Suzuki, Yutaka Hasegawa, Mareki Honma, Hiroaki Tanaka, Kosei Ishimura, Yasuhiro Murata, Reiho Shimomukai, Tomohiro Tachi, Kazuya Saito, Naohiko Watanabe, Nobutaka Bando, Osamu Kameya, Yoshinori Yonekura, Mamoru Sekido, Yoshiyuki Inoue, Hikaru Sakamoto, Nozomu Kogiso, Yasuhiro Shoji, Hideo Ogawa, Kenta Fujisawa, Masanao Narita, Hiroshi Shibai, Hideyuki Fuke, Kenta Uehara, Shoko Koyama
    ADVANCES IN SPACE RESEARCH, 63(1) 779-793, Jan, 2019  Peer-reviewedLead author
  • Yoshiyuki Inoue, Akihiro Doi
    ASTROPHYSICAL JOURNAL, 869(2) 114-114, Dec, 2018  Peer-reviewedCorresponding author
  • Masanori Nakamura, Keiichi Asada, Kazuhiro Hada, Hung-Yi Pu, Scott Noble, Chihyin Tseng, Kenji Toma, Motoki Kino, Hiroshi Nagai, Kazuya Takahashi, Juan-Carlos Algaba, Monica Orienti, Kazunori Akiyama, Akihiro Doi, Gabriele Giovannini, Marcello Giroletti, Mareki Honma, Shoko Koyama, Rocco Lico, Kotaro Niinuma, Fumie Tazaki
    ASTROPHYSICAL JOURNAL, 868(2) 146, Dec, 2018  Peer-reviewed
  • Kazuhiro Hada, Akihiro Doi, Kiyoaki Wajima, Filippo D’Ammando, Monica Orienti, Marcello Giroletti, Gabriele Giovannini, Masanori Nakamura, Keiichi Asada
    The Astrophysical Journal, 860(2) 141-141, Jun 21, 2018  Peer-reviewed
  • Hagiwara Yoshiaki, Doi Akihiro, Hachisuka Kazuya, Horiuchi Shinji
    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 70(3), Jun, 2018  Peer-reviewed
  • Akihiro Doi, Kazuhiro Hada, Motoki Kino, Kiyoaki Wajima, Satomi Nakahara
    Astrophysical Journal Letters, 857(1) L6, Apr 10, 2018  Peer-reviewedLead author
  • Satomi Nakahara, Akihiro Doi, Yasuhiro Murata, Kazuhiro Hada, Masanori Nakamura, Keiichi Asada
    ASTROPHYSICAL JOURNAL, 854(2), Feb, 2018  Peer-reviewed
  • Yoshiyuki Inoue, Akihiro Doi, Yasuyuki T. Tanaka, Marek Sikora, Grzegorz M. Madejski
    ASTROPHYSICAL JOURNAL, 840(1), May, 2017  Peer-reviewed
  • Satomi Nakahara, Akihiro Doi, Yasuhiro Murata, Kazuhiro Hada, Masanori Nakamura, Keiichi Asada
    GALAXIES, 4(4), Dec, 2016  
  • Sugiyama, Koichiro, Fujisawa, Kenta, Hachisuka, Kazuya, Yonekura, Yoshinori, Motogi, Kazuhito, Sawada-Satoh, Satoko, Matsumoto, Naoko, Hirano, Daiki, Hayashi, Kyonosuke, Kobayashi, Hideyuki, Kawaguchi, Noriyuki, Shibata, Katsunori M, Honma, Mareki, Hirota, Tomoya, Murata, Yasuhiro, Doi, Akihiro, Ogawa, Hideo, Kimura, Kimihiro, Niinuma, Kotaro, Chen, Xi, Xia, Bo, Li, Bin, Sorai, Kazuo, Momose, Munetake, Saito, Yu, Takaba, Hiroshi, Omodaka, Toshihiro, Kim, Kee-Tae, Shen, Zhiqiang
    Publications of the Astronomical Society of Japan, 68(5) 72, Oct, 2016  Peer-reviewed
  • Akihiro Doi, Tomoaki Oyama, Yusuke Kono, Aya Yamauchi, Syunsaku Suzuki, Naoko Matsumoto, Fumie Tazaki
    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 68(5) 73, Oct, 2016  Peer-reviewedLead author
  • Yoshiaki Hagiwara, Shinji Horiuchi, Akihiro Doi, Makoto Miyoshi, Philip G. Edwards
    ASTROPHYSICAL JOURNAL, 827(1), Aug, 2016  Peer-reviewed
  • Akihiro Doi, Yoshiyuki Inoue
    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 68(4) 56, Aug, 2016  Peer-reviewedLead author
  • Tanaka Hiroaki, Hiraku Sakamoto, Akiya Inagaki, Kosei Ishimura, Akihiro Doi, Yusuke Kono, Tomoaki Oyama, Kazuki Watanabe, Yu Oikawa, Takeshi Kuratomi
    JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES, 27(6) 764-773, Apr, 2016  Peer-reviewed
  • Shoko Koyama, Motoki Kino, Marcello Giroletti, Akihiro Doi, Hiroshi Nagai, Kazuhiro Hada, Kotaro Niinuma, Monica Orienti, Gabriele Giovannini, Eduardo Ros, Tuomas Savolainen, Miguel A, P?rez-Torres, Thomas, P. Krichbaum
    Astronomy & Astrophysics, 586 113, Feb, 2016  Peer-reviewed
    Context. High-resolution millimeter wave very-long-baseline interferometry (mm-VLBI) is an ideal tool for probing the structure at the base of extragalactic jets in detail. The TeV blazar Mrk 501 is one of the best targets among BL Lac objects for studying the nature of off-axis jet structures because it shows different jet position angles at different scales. Aims: The aim of this study is to investigate the properties of the off-axis jet structure through high-resolution mm-VLBI images at the jet base and physical parameters such as kinematics, flux densities, and spectral indices. Methods: We performed Very Long Baseline Array (VLBA) observations over six epochs from 2012 February to 2013 February at 43 GHz. Quasi-simultaneous Global Millimeter VLBI Array (GMVA) observations at 86 GHz were performed in May 2012. Results: We discover a new jet component at the northeast direction from the core in all the images at 43 and 86 GHz. The new component shows the off-axis location from the persistent jet extending to the southeast. The 43 GHz images reveal that the scattering of the positions of the NE component is within ~0.2 mas. The 86 GHz data reveals a jet component located 0.75 mas southeast of the radio core. We also discuss the spectral indices between 43 and 86 GHz, where the northeast component has steeper spectral index and the southeast component has comparable or flatter index than the radio core does.
  • Nozomu KOGISO, Ryo KODAMA, Kimihiro KIMURA, Yasutaka SATOU, Akihiro DOI, Hiroaki TANAKA
    AEROSPACE TECHNOLOGY JAPAN, THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 15 91-100, 2016  

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