研究者業績

瀧本 幸司

タキモト コウジ  (Koji Takimoto)

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 日本学術振興会特別研究員-PD
学位
博士(理学)(2022年3月 関西学院大学)
修士(理学)(2019年3月 関西学院大学)

連絡先
takimoto.kohjijaxa.jp
研究者番号
40967569
ORCID ID
 https://orcid.org/0000-0002-8405-9549
J-GLOBAL ID
202201014396272085
researchmap会員ID
R000036452

論文

 17
  • Richard M. Feder, James J. Bock, Yun-Ting Cheng, Asantha Cooray, Phillip M. Korngut, Shuji Matsuura, Chi H. Nguyen, Kohji Takimoto, Michael Zemcov, CIBER collaboration
    2025年1月29日  
    Precise, unbiased measurements of extragalactic background anisotropies require careful treatment of systematic effects in fluctuation-based, broad-band intensity mapping measurements. In this paper we detail improvements in methodology for the Cosmic Infrared Background ExpeRiment (CIBER), concentrating on flat field errors and source masking errors. In order to bypass the use of field differences, which mitigate flat field errors but reduce sensitivity, we characterize and correct for the flat field on pseudo-power spectra, which includes both additive and multiplicative biases. To more effectively mask point sources at 1.1 $\mu$m and 1.8 $\mu$m, we develop a technique for predicting masking catalogs that utilizes optical and NIR photometry through random forest regression. This allows us to mask over two Vega magnitudes deeper than the completeness limits of 2MASS alone, with errors in the shot noise power remaining below $<10\%$ at all masking depths considered. Through detailed simulations of CIBER observations, we validate our formalism and demonstrate unbiased recovery of the sky fluctuations on realistic mocks. We demonstrate that residual flat field errors comprise $<20\%$ of the final CIBER power spectrum uncertainty with this methodology.
  • Richard M. Feder, James J. Bock, Yun-Ting Cheng, Asantha Cooray, Phillip M. Korngut, Shuji Matsuura, Jordan Mirocha, Chi H. Nguyen, Kohji Takimoto, Kohji Tsumura, Ryan Wills, Michael Zemcov, CIBER collaboration
    2025年1月29日  
    We present new anisotropy measurements in the near-infrared (NIR) for angular multipoles $300<\ell<10^5$ using imaging data at 1.1 $\mu$m and 1.8 $\mu$m from the fourth flight of the Cosmic Infrared Background ExpeRiment (CIBER). Using improved analysis methods and higher quality fourth flight data, we detect surface brightness fluctuations on scales $\ell<2000$ with CIBER auto-power spectra at $\sim14\sigma$ and 18$\sigma$ for 1.1 and 1.8 $\mu$m, respectively, and at $\sim10\sigma$ in cross-power spectra. The CIBER measurements pass internal consistency tests and represent a $5-10\times$ improvement in power spectrum sensitivity on several-arcminute scales relative to that of existing studies. Through cross-correlations with tracers of diffuse galactic light (DGL), we determine that scattered DGL contributes $<10\%$ to the observed fluctuation power at high confidence. On scales $\theta > 5'$, the CIBER auto- and cross-power spectra exceed predictions for integrated galactic light (IGL) and integrated stellar light (ISL) by over an order of magnitude, and are inconsistent with our baseline IGL+ISL+DGL model at high significance. We cross-correlate two of the CIBER fields with 3.6 $\mu$m and 4.5 $\mu$m mosaics from the Spitzer Deep Wide-Field Survey and find similar evidence for departures from Poisson noise in Spitzer-internal power spectra and CIBER $\times$ Spitzer cross-power spectra. A multi-wavelength analysis indicates that the auto-power of the fluctuations at low-$\ell$ is bluer than the Poisson noise from IGL and ISL; however, for $1' <\theta < 10'$, the cross-correlation coefficient $r_{\ell}$ of nearly all band combinations decreases with increasing $\theta$, disfavoring astrophysical explanations that invoke a single correlated sky component.
  • Shunsuke Nakagawa, Chinathip Narongphun, Zamba Leonel, Hari Shrestha, Isami Kato, Emino Fukumoto, Rodrigo Cordova, Victor Hugo Schulz, Necmi Cihan Örger, Kei Sano, Takao Nakagawa, Koji Takimoto, Shuji Matsuura, Kohji Tsumura, Aoi Takahashi, Daisuke Nakayama, Akimasa Ojika, Rin Sato, Keenan A. A. Chatar, Yukihisa Otani, Ezra Fielding, Kentaro Hayashida, Hayato Tanaka, Eyoas E. Areda, Bastien B. A. Morelle, Hisataka Kawasaki, Umi Enokidani, Reynel Josue Galindo Rosales, Karaki Shohei, Ichiro Jikuya
    Space Telescopes and Instrumentation 2024: Optical, Infrared, and Millimeter Wave 13092 117-117 2024年8月23日  
    Extragalactic Background Light (EBL), the cumulative light from outside the galaxy, is a crucial observational target for understanding the history of the universe. We are developing a CubeSat; VERTECS (Visible Extragalactic background RadiaTion Exploration by CubeSat) with a 6U size (approximately 10 × 20 × 30 cm), equipped with Solar Array Wings (SAW). Our mission is to conduct extensive observations of the visible EBL. The satellite is designed to operate in a sun-synchronous orbit at an altitude of 500-680 km (approximately 15 orbits per day) and observe the EBL on the shadow side to avoid stray light from the Sun and Earth. To observe EBL, a high-performance CMOS sensor, attitude control devices, and high-speed communication equipment X-band are essential. We should note that these components these components consume a significant amount of power. Therefore, some strategic operational plans are necessary to operate this CubeSat within the limited power resources. In addition, VERTECS needs to meet its mission requirements, conducting 10 observations, 4 data downlinks, and 1 command uplink within a day. We have constructed some operational scenarios utilizing attitude control and SAW to meet these requirements, and we also constructed a power budget simulation for VERTECS. In this presentation, we describe how we plan to operate VERTECS utilizing the subsystems and the results of the power simulation during the operation.
  • Hisataka Kawasaki, Eyoas E. Areda, Hideo Matsuhara, Hirokazu Masui, Kohji Takimoto, Bastien B. A. Morelle, Shuji Matsuura, Takao Nakagawa, Umi Enokidani, Yuki Hirose, Kei Sano
    Space Telescopes and Instrumentation 2024: Optical, Infrared, and Millimeter Wave 13092 116-116 2024年8月23日  
    The extragalactic background light (EBL) is the integrated emission from out of our Galaxy.Its observation is crucial for revealing the history of star-formation from the early universe to the present epoch. Visible Extragalactic background RadiaTion Exploration by CubeSat (VERTECS) is a 6U astronomical satellite to observe the EBL in visible wavelength from 0.4 µm to 0.8 µm. To observe the EBL, a telescope with 11 lenses and a high-performance CMOS sensor are equipped within 3U volume. The remaining 3U comprises the bus section mainly based on the bus design previously developed at Kyushu Institute of Technology. This paper describes the design and verification processes of the structure and thermal model of the satellite to fulfill the interface and mission requirements. From a mission perspective, the precise attitude and orbit control system unit is mounted on the same interface plate as the telescope to meet stringent pointing stability requirements during observations. The purpose of the stiff design of this interface plate is to minimize structural deformation. Furthermore, integrating multiple external antennas with relatively large X-band and S-band communication units require effective routing harness management. Static stress analysis is performed under the quasi-static loading condition. In addition, modal analysis is also conducted to fulfill the strength and stiffness requirements of the launcher. A series of mechanical environmental tests (shock, random, and sinusoidal vibrations) have been conducted to verify the design and analysis results. The results showed that designed model can fundamentally withstand the launch environment.
  • Hayato Tanaka, Hideo Matsuhara, Takao Nakagawa, Koji Takimoto, Aoi Takahashi, Satoshi Ikari, Rodrigo Cordova, Victor Hugo Schulz, Necmi Cihan Örger, Shunsuke Nakagawa, Shuji Matsuura, Kohji Tsumura
    Space Telescopes and Instrumentation 2024: Optical, Infrared, and Millimeter Wave 13092 115-115 2024年8月23日  
    The Visible Extragalactic background RadiaTion Exploration by CubeSat (VERTECS) is designed for observing Extragalactic Background Light(EBL). VERTECS mission requires attitude control stability better than 10 arcsec (1σ) per minute, pointing accuracy better than 0.1 deg, and the slew rate faster than 1 deg per sec. We discuss the software-in-the-loop (SIL) attitude simulator simulation to verify whether the current Attitude Determination Control System (ADCS) design and the planned orbit can meet the requirements for EBL observations. We simulate the attitude control system with the simulation software, taking into account the attitude control commands, the parameters of the ADCS hardware, and the expected attitude disturbances in the assumed orbit. This simulation shows the sequence of attitude maneuvers needed to meet the requirement. The simulation results indicate that the current observation sequence is feasible.

MISC

 58
  • 玉井, 桃子, 松浦, 周二, 橋本, 遼, 中川, 智矢, 中畑, 秀太, 花井, 翔, 瀧本, 幸司, 佐野, 圭, 中川, 俊輔, 津村, 耕司, 高橋, 葵, 和田, 武彦, ZEMCOV, Michael, BOCK, James, CIBER-2 collaboration,
    観測ロケットシンポジウム2023 講演集 2024年2月  
    レポート番号: Ⅴ-3
  • TOME Yuto, SANO Kei, NAKAGAWA Shunsuke, KUROSAKI Kana, NISHIOKA Masahiro, MATSUURA Shuji, HIROSE Yuki, OJIKA Akimasa, TSUMOTO Akane, OHARA Yuki, NAKAGAWA Takao, TAKAHASHI Aoi, TAKIMOTO Kohji, TANAKA Hayato
    日本天文学会年会講演予稿集 2024 2024年  
  • HIROSE Yuki, MATSUURA Shuji, OJIKA Akimasa, TSUMOTO Akane, OHARA Yuki, SANO Kei, TOME Yuto, KAWASAKI Hisataka, NAKAGAWA Shunsuke, SATO Rin, HASHIMOTO Ryo, TSUMURA Kohji, NAKAGAWA Takao, TAKIMOTO Kohji, TAKAHASHI Aoi, TANAKA Hayato
    日本天文学会年会講演予稿集 2024 2024年  
  • TAKIMOTO Kohji, NAKAGAWA Takao, TAKAHASHI Aoi, TANAKA Hayato, SANO Kei, KAWASAKI Hisataka, TOME Yuto, NAKAGAWA Shunsuke, KUROSAKI Kana, SATO Rin, HASHIMOTO Ryo, MATSUURA Shuji, HIROSE Yuki, OJIKA Akimasa, TSUMOTO Akane, OHARA Yuki, TSUMURA Kohji
    日本天文学会年会講演予稿集 2024 2024年  
  • TAKAHASHI Aoi, TANAKA Hayato, YASUDA Yoshinao, TAKIMOTO Kohji, NAKAGAWA Takao, OJIKA Akimasa, TSUMOTO Akane, OHARA Yuki, HIROSE Yuki, MATSUURA Shuji, TOME Yuto, NISHIOKA Masahiro, NAKAGAWA Shunsuke, KUROSAKI Kana, SANO Kei
    日本天文学会年会講演予稿集 2024 2024年  

講演・口頭発表等

 7
  • 瀧本幸司
    2024年12月4日  招待有り
  • 瀧本幸司
    2024年12月3日  招待有り
  • 櫛引洸佑, 津村耕司, 東谷千比呂, 瀧本幸司, 大宮正士, 大金原
    2024年度光赤天連シンポジウム「光赤天連の長期的ロードマップおよび若手育成支援」 2024年9月19日 石垣美歩、栗田光樹夫、児玉忠恭、高田昌広、長尾透、橋本拓也、 本田充彦、本原顕太郎、吉田二美
    2024年度のシンポジウムでは「光赤天連の長期的ロードマップおよび若手育成支援」と題して、日本における光赤外天文学の将来設計のための議論を行う。 日本において光赤外天文学を推進する研究機関として中核を担うのは国立天文台と宇宙科学研究所であろう。 両機関が考える地上およびスペースから行う光赤外天文学の展望を両機関のトップをお招きし、2020年代、2030年代に実現すべきと考えている課題についてじっくり話を伺う。 現行プロジェクトの報告を聞き、海外の動向を共有し、光赤天連将来計画検討専門委員会の委員での検討状況の報告を聞く。 ロードマップに提案された個々の計画についての説明を聞く機会も設ける。 さらに、最近活発になってきた産業界の宇宙進出についてのセッションを設け、光赤天のコミュニティとどのように協力関係を構築できるか考える機会を設ける。 また、長期計画実現において若い戦力は欠かせないため、若手研究者が研究発表するセッションも設ける。 博士号を取ったばかりの研究者や今年度博士号を取る予定の学生が自身の研究を発表する場としていただく。 本シンポジウムは、今後の天文学の展望を共有し、光赤外天文学における日本のロードマップ策定について議論する場とする。
  • 瀧本幸司
    九州工業大学 GYMLABO 2024年5月7日  招待有り
  • 瀧本幸司, 佐野圭, 松浦周二, 橋本遼, 河野有哉, 松見知香, 中川智矢, 高濱伶緒, 中畑秀太, 津村耕司, Michael Zemcov(RIT, James Bock(Caltech/JPL, Daehee Lee(KASI, Shiang-Yu Wang(ASIAA, ほかCIBER-2チーム
    第11回 可視赤外線観測装置技術ワークショップ 2022 2022年12月22日
  • Kohji Takimoto, James J. Bock, Yun-Ting Cheng, Asantha Cooray, Richard M. Feder, Ryo Hashimoto, Grigory Heaton, Viktor Hristov, Yuya Kawano, Phillip Korngu, Dae-Hee Lee, Chika Matsumi, Shuji Matsuura, Tomoya Nakagawa, Chi H. Nguyen, Kazuma Noda, Mikey Ortiz, Won-Kee Park, Kei Sano, Serena Tramm, Kohji Tsumura, Michael Zemcov
    10 th International Symposium on Applied Engineering and Sciences (SAES2022) 2022年12月14日
  • 瀧本幸司
    ISAS Astrophisics Colloquia 2022年3月  招待有り

担当経験のある科目(授業)

 3

所属学協会

 2

共同研究・競争的資金等の研究課題

 4