宇宙科学広報・普及主幹付

土居 明広

ドイ アキヒロ  (Akihiro DOI)

基本情報

所属
国立研究開発法人宇宙航空研究開発機構 宇宙科学研究所 宇宙物理学研究系 助教
総合研究大学院大学 物理科学研究科 宇宙科学専攻 助教
学位
博士 (理学)(2005年3月 東京大学)

研究者番号
90403641
ORCID ID
 https://orcid.org/0000-0003-4384-9568
J-GLOBAL ID
201101033666007265
researchmap会員ID
B000004312

論文

 111
  • 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 2024年8月23日  
  • 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 2024年8月23日  
  • 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 2024年8月23日  
  • 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 2024年8月21日  
  • Takayuki J Hayashi, Akihiro Doi, Hiroshi Nagai
    Monthly Notices of the Royal Astronomical Society 530(3) 2590-2607 2024年4月15日  
    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.

MISC

 66

講演・口頭発表等

 28

共同研究・競争的資金等の研究課題

 12