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Chief Scientist Laboratories High Energy Astrophysics Laboratory

Chief Scientist: Toru Tamagawa (D.Sci.)

Research Summary

Toru  Tamagawa(D.Sci.)

Immediately after the Big Bang, the beginning of our universe, only hydrogen and helium existed. However, nucleosynthesis in the supernova explosions over the course of 13.8 billion years led to the evolution of a world brimming with the many different elements we have today. By using satellites to detect X-rays and gamma-rays, we are observing the synthesized elements at their actual source. Our goal is to comprehensively elucidate the scenarios for the formation of the elements in the universe. We are also conducting observations of the extreme conditions near black holes and neutron stars that are unreachable on Earth, to see how far our knowledge of physics can be applied.

Main Research Fields

  • Mathematical & Physical Sciences

Related Research Fields

  • Engineering
  • Particle/Nuclear/Cosmic ray/Astro physics
  • Astronomy


  • Astrophysics and space science
  • Payload development onboard satellites
  • Radiation detection technology

Selected Publications

  • 1. Baldini, L., et al.:
    "Design, construction, and test of the Gas Pixel Detectors for the IXPE mission"
    Astroparticle Physics 133, 102628 (2021).
  • 2. Abarr, Q., et al.:
    "XL-Calibur - a second-generation balloon-borne hard X-ray polarimetry mission"
    Astroparticle Physics 126, 102529 (2021).
  • 3. Nakahira, S.; et al.:
    "MAXI/SSC All-sky maps from 0.7 keV to 4 keV"
    Publications of the Astronomical Society of Japan 72, 17 (2020).
  • 4. Tamagawa, T., et al.:
    "Multiplexing lobster-eye optics: a concept for wide-field x-ray monitoring"
    Journal of Astronomical Telescopes, Instruments, and Systems 6, 025003 (2020).
  • 5. Gu, L., et al.:
    "Observations of a Pre-Merger Shock in Colliding Clusters of Galaxies"
    Nature Astronomy 3, 838 (2019).
  • 6. Kitaguchi, T., et al.:
    "A convolutional neural network approach for reconstructing polarization information of photoelectric X-ray polarimeters"
    Nuclear Inst. and Methods in Physics Research A 942, 162389 (2019).
  • 7. O’dell, S., et al.:
    "The Imaging X-ray Polarimetry Explorer (IXPE): technical overview"
    Proceedings of the SPIE 10699, 106991X (2018).
  • 8. Yatabe, F., et al.:
    "An application of the Ghosh & Lamb model to the accretion-powered X-ray pulsar X Persei"
    Publications of the Astronomical Society of Japan 70, 89 (2018).
  • 9. The Hitomi Collaboration:
    "Solar abundance ratios of the iron-peak elements in the Perseus cluster"
    Nature 551, 478 (2017).
  • 10. The Hitomi Collaboration:
    "The quiescent intracluster medium in the core of the Perseus cluster"
    Nature 535, 117 (2016).

Recent Research Results

Related Links

Lab Members

Principal investigator

Toru Tamagawa
Chief Scientist

Core members

Tatehiro Mihara
Senior Research Scientist
Takao Kitaguchi
Research Scientist
Makoto Sawada
Research Scientist
Yuanhui Zhou
Junior Research Associate
Jin Li
Junior Research Associate
Hiroki Sato
Student Trainee
Kento Sakai
Student Trainee
Wataru Iwakiri
Visiting Scientist
Liyi Gu
Visiting Scientist
Toshiki Sato
Visiting Scientist
Satoshi Nakahira
Visiting Scientist
Kazumi Asai
Research Part-time Worker I

Contact Information

RIBF Bldg. Rm. 402,
2-1 Hirosawa,
Wako, Saitama
351-0198, Japan
Email: tamagawa [at] riken.jp