Study of 3-dimensional structure of galaxies and cosmological magnetic fields with large low-frequency polarization survey

• Project/Area Number: 16H05999
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Astronomy
• Research Institution: Kumamoto University
• Principal Investigator: Takahashi Keitaro 熊本大学, 大学院先端科学研究部(理), 准教授 (80547547)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥21,840,000 (Direct Cost: ¥16,800,000、Indirect Cost: ¥5,040,000); Fiscal Year 2019: ¥5,330,000 (Direct Cost: ¥4,100,000、Indirect Cost: ¥1,230,000); Fiscal Year 2018: ¥5,330,000 (Direct Cost: ¥4,100,000、Indirect Cost: ¥1,230,000); Fiscal Year 2017: ¥5,330,000 (Direct Cost: ¥4,100,000、Indirect Cost: ¥1,230,000); Fiscal Year 2016: ¥5,850,000 (Direct Cost: ¥4,500,000、Indirect Cost: ¥1,350,000)
• Keywords: 宇宙磁場 / 電波天文学 / 銀河 / SKA / ファラデートモグラフィ / 宇宙再電離 / 21cm線 / 宇宙物理 / パルサー / 宇宙論

Outline of Final Research Achievements

We studied Faraday tomography, which is a method to analyze wide-band polarimetry data and can probe cosmic magnetism. First, we tested the performance of the RM CLEAN and QU-fit softwares we developed so far, using simulated data. Second, we predicted Faraday dispersion function of galaxies with a model of turbulent and coherent magnetic fields, thermal electron distribution and cosmic-ray electron distribution. Finally, we developed a new algorithm of Faraday tomography, introducing the concept of sparse modeling.

Academic Significance and Societal Importance of the Research Achievements

電波望遠鏡の広帯域化が進んでいく中で、ファラデートモグラフィは今後の偏波解析のスタンダードになっていくと考えられる。本研究で開発したソフトウェアや蓄積したノウハウは宇宙磁場研究にブレイクスルーをもたらし、そのまま将来の大型電波望遠鏡SKAや他の広帯域電波望遠鏡にも適用可能で、本研究は今後10年スケールの長期的な将来性がある。またソフトウェアの開発には多くの大学院生が関わってきており、国際的に活躍できる電波天文学者を育成し国際研究者ネットワークを構築するのに非常に効果的なプロジェクトであった。

Research Products

• [Int'l Joint Research] CSIRO/カーティン大学/メルボルン大学(オーストラリア)
• [Int'l Joint Research] CSIRO/メルボルン大学/カーティン大学(オーストラリア)
• [Int'l Joint Research] ハンブルグ大学(ドイツ)
• [Int'l Joint Research] メルボルン大学/カーティン大学/CSIRO(オーストラリア)
• [Int'l Joint Research] メルボルン大学/CSIRO/カーティン大学(オーストラリア)
• [Journal Article] Faraday Dispersion Function of Disk Galaxies with Axisymmetric Global Magnetic Fields. I. (2020)
  • Author(s): Eguchi, Haruya; Suzuki, Masaki; Miyashita, Yoshimitsu; Ideguchi, Shinsuke; Takahashi, Keitaro
  • Journal Title: The Astrophysical Journal Volume: 899 Issue: 2 Pages: 122-122
  • DOI: 10.3847/1538-4357/ab9f9e
  • Peer Reviewed / Open Access
• [Journal Article] An iterative reconstruction algorithm for Faraday tomography (2020)
  • Author(s): Cooray Suchetha、Takeuchi Tsutomu T、Akahori Takuya、Miyashita Yoshimitsu、Ideguchi Shinsuke、Takahashi Keitaro、Ichiki Kiyotomo
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 500 Issue: 4 Pages: 5129-5141
  • DOI: 10.1093/mnras/staa3580
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Detailed study of detection method for ultralow frequency gravitational waves with pulsar spin-down rate statistics (2019)
  • Author(s): Hisano Shinnosuke、Yonemaru Naoyuki、Kumamoto Hiroki、Takahashi Keitaro
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 487 Issue: 1 Pages: 97-103
  • DOI: 10.1093/mnras/stz1285
  • Peer Reviewed / Open Access
• [Journal Article] Constraints on ultra-low-frequency gravitational waves with statistics of pulsar spin-down rates (2019)
  • Author(s): Kumamoto Hiroki、Imasato Yuya、Yonemaru Naoyuki、Kuroyanagi Sachiko、Takahashi Keitaro
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 489 Issue: 3 Pages: 3547-3552
  • DOI: 10.1093/mnras/stz2321
  • Peer Reviewed / Open Access
• [Journal Article] The intergalactic magnetic field probed by a giant radio galaxy (2019)
  • Author(s): O’Sullivan S. P.、... Takahashi K.（30名中24番目）
  • Journal Title: Astronomy & Astrophysics Volume: 622 Pages: A16-A16
  • DOI: 10.1051/0004-6361/201833832
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Sensitivity of new detection method for ultra-low frequency gravitational waves with pulsar spin-down rate statistics (2018)
  • Author(s): Yonemaru Naoyuki、Kumamoto Hiroki、Takahashi Keitaro、Kuroyanagi Sachiko
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 478 Issue: 2 Pages: 1-7
  • DOI: 10.1093/mnras/sty976
  • Peer Reviewed / Open Access
• [Journal Article] Detectability of 21 cm-signal during the Epoch of Reionization with 21-cm-Lyman-α emitter cross-correlation II: Foreground contamination (2018)
  • Author(s): Yoshiura S、Line J L B、Kubota K、Hasegawa K、Takahashi K
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 479 Issue: 2 Pages: 2767-2776
  • DOI: 10.1093/mnras/sty1472
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Detectability of the 21-cm signal during the epoch of reionization with 21-cm Lyman α emitter cross-correlation I (2018)
  • Author(s): Kubota Kenji、Yoshiura Shintaro、Takahashi Keitaro、Hasegawa Kenji、Yajima Hidenobu、Ouchi Masami、Pindor B、Webster R L
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 479 Issue: 2 Pages: 2754-2766
  • DOI: 10.1093/mnras/sty1471
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Impact of EDGES 21-cm global signal on the primordial power spectrum (2018)
  • Author(s): Yoshiura, Shintaro and Takahashi, Keitaro and Takahashi, Tomo
  • Journal Title: Physical Reivew D Volume: 98 Issue: 6 Pages: 63529-63529
  • DOI: 10.1103/physrevd.98.063529
  • Peer Reviewed / Open Access
• [Journal Article] Optimum frequency of Faraday tomography to explore the intergalactic magnetic field in filaments of galaxies (2018)
  • Author(s): Akahori Takuya、Ideguchi Shinsuke、Aoki Takahiro、Takefuji Kazuhiro、Ujihara Hideki、Takahashi Keitaro
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 70 Issue: 6 Pages: 115-115
  • DOI: 10.1093/pasj/psy124
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Performance test of QU-fitting in cosmic magnetism study (2018)
  • Author(s): Miyashita Yoshimitsu、Ideguchi Shinsuke、Nakagawa Shouta、Akahori Takuya、Takahashi Keitaro
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 482 Issue: 2 Pages: 2739-2749
  • DOI: 10.1093/mnras/sty2862
  • Peer Reviewed / Open Access
• [Journal Article] Study of systematics effects on the cross power spectrum of 21?cm line and cosmic microwave background using Murchison Widefield Array data (2018)
  • Author(s): Yoshiura S、Ichiki K、Pindor B、Takahashi K、Tashiro H、Trott C M
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 483 Issue: 2 Pages: 2697-2711
  • DOI: 10.1093/mnras/sty3248
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] The variance of dispersion measure of high-redshift transient objects as a probe of ionized bubble size during reionization (2018)
  • Author(s): Yoshiura Shintaro、Takahashi Keitaro
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 473 Issue: 2 Pages: 1570-1575
  • DOI: 10.1093/mnras/stx2462
  • Peer Reviewed / Open Access
• [Journal Article] Constraining the epoch-of-reionization model parameters with the 21-cm bispectrum (2017)
  • Author(s): Hayato Shimabukuro, Shintaro Yoshiura, Keitaro Takahashi, Shuichiro Yokoyama, Kiyotomo Ichiki
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 468 Issue: 2 Pages: 1542-1550
  • DOI: 10.1093/mnras/stx530
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Study of the Vertical Magnetic Field in Face-on Galaxies Using Faraday Tomography (2017)
  • Author(s): Ideguchi Shinsuke、Tashiro Yuichi、Akahori Takuya、Takahashi Keitaro、Ryu Dongsu
  • Journal Title: The Astrophysical Journal Volume: 843 Issue: 2 Pages: 146-146
  • DOI: 10.3847/1538-4357/aa79a1
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Constraining the contribution of galaxies and active galactic nuclei to cosmic reionization (2017)
  • Author(s): Yoshiura Shintaro、Hasegawa Kenji、Ichiki Kiyotomo、Tashiro Hiroyuki、Shimabukuro Hayato、Takahashi Keitaro
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: 471 Issue: 3 Pages: 3713-3726
  • DOI: 10.1093/mnras/stx1754
  • Peer Reviewed / Open Access
• [Journal Article] Cosmic magnetism in centimeter- and meter-wavelength radio astronomy (2017)
  • Author(s): Akahori Takuya、Nakanishi Hiroyuki、Sofue Yoshiaki、Fujita Yutaka、Ichiki Kiyotomo、Ideguchi Shinsuke、Kameya Osamu、Kudoh Takahiro、Kudoh Yuki、Machida Mami、Miyashita Yoshimitsu、Ohno Hiroshi、Ozawa Takeaki、Takahashi Keitaro、Takizawa Motokazu、Yamazaki Dai G
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 70 Issue: 1 Pages: 1-44
  • DOI: 10.1093/pasj/psx123
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Performance test of RM CLEAN and its evaluation with chi-square value (2016)
  • Author(s): Y. Miyashita, S. Ideguchi, K. Takahashi
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 68 Issue: 3 Pages: 44-44
  • DOI: 10.1093/pasj/psw039
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Probing primordial non-Gaussianity consistency relation with galaxy surveys (2016)
  • Author(s): D. Yamauchi, K. Takahashi
  • Journal Title: Physical Review D Volume: 93 Issue: 12 Pages: 123506-123506
  • DOI: 10.1103/physrevd.93.123506
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Journal Article] Expected constraints on models of the epoch of reionization with the variance and skewness in redshifted 21cm-line fluctuations (2016)
  • Author(s): K. Kubota, S. Yoshiura, H. Shimabukuro, K. Takahashi
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 68 Issue: 4 Pages: 61-61
  • DOI: 10.1093/pasj/psw059
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Journal Article] Rapid merger of binary primordial black holes: An implication for GW150914 (2016)
  • Author(s): K. Hayasaki, K. Takahashi, Y. Sendouda, S. Nagataki
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 68 Issue: 4 Pages: 66-66
  • DOI: 10.1093/pasj/psw065
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Presentation] Gravitational Wave Detection with Pulsar Timing Array (2020)
  • Author(s): Keitaro Takahashi
  • Organizer: KEK-PH + KEK-Cosmo Gravitational Wave
  • Int'l Joint Research / Invited
• [Presentation] Gravitational Wave Detection with Pulsar Timing Array (2019)
  • Author(s): Keitaro Takahashi
  • Organizer: East Asia SKA Workshop
  • Int'l Joint Research
• [Presentation] 「Pulsar studies in SKA Japan」 (2019)
  • Author(s): Keitaro Takahashi
  • Organizer: Asia SKA Initiative On NS Meeting
  • Int'l Joint Research / Invited
• [Presentation] 「Toward the Detection of Cosmological HI 21cm line Emission」 (2019)
  • Author(s): Keitaro Takahashi
  • Organizer: 「加速宇宙」シンポジウム
  • Int'l Joint Research / Invited
• [Presentation] 「Pulsar Timing Array」 (2019)
  • Author(s): Keitaro Takahashi
  • Organizer: RESCEU workshop on Space Gravitational Wave Detection
  • Int'l Joint Research / Invited
• [Presentation] 「次世代低周波電波望遠鏡Square Kilometre Array」 (2018)
  • Author(s): 高橋慶太郎
  • Organizer: 電子情報通信学会アンテナ・伝搬研究会
  • Invited
• [Presentation] 「SKAとVLBIによるパルサー研究の未来」 (2018)
  • Author(s): 高橋慶太郎
  • Organizer: VLBI懇談会シンポジウム
  • Invited
• [Presentation] 「機械学習によるパルサーサーチ」 (2018)
  • Author(s): 高橋慶太郎
  • Organizer: 宇宙電波懇談会シンポジウム
• [Presentation] Scientific activities in the Japanese consortium (2017)
  • Author(s): Keitaro Takahashi
  • Organizer: MWA Project Meeting（イタリア・パドヴァ）
  • Int'l Joint Research / Invited
• [Presentation] 中性水素21cm線で探る初代天体と宇宙再電離 (2017)
  • Author(s): 高橋慶太郎
  • Organizer: 日本物理学会シンポジウム（宇都宮大学）
  • Invited
• [Presentation] 次世代電波望遠鏡SKAによるパルサー研究の将来 (2017)
  • Author(s): 高橋慶太郎
  • Organizer: 中性子星の観測と理論～研究活性化ワークショップ2017（国立天文台）
  • Invited