Kohji Tsumura

Name Kohji Tsumura
Title Assistant Professor
Platform Advanced Basic Science
Research Fields Infrared Astronomy
Research Subjects Astronomy and planetary science through observations of infrared diffuse radiation
Academic Society Membership The Astronomical Society of Japan, The Japanese Society for Planetary Science, Japan Geoscience Union, Japanese Spcoety for Education and Popularization of Astronomy
Mentor Information
Title Name Affiliation
Professor ICHIKAWA Takashi Graduate School of Science

Research Outline

According to the Olbers' paradox, the sky should be bright even at night with the assumption of an infinite and eternal static universe. Although this assumption does not hold true under the current understanding of the universe under the Big-Bang and the Inflation scheme, the night sky has some level of brightness. Brightness of the night sky in the near-infrared includes (1) the zodiacal light from the solar system, (2) the diffuse galactic light from our Galaxy, and (3) the extragalactic background light from outside of our Galaxy. I studied the characteristics of the infrared diffuse radiation from the near-by space (solar system) to the farthest universe.

Observation from space is required to observe the diffuse radiation because of the strong atmospheric foreground radiation. Thus we conducted the rocket-born experiment CIBER (Cosmic Infrared Background ExpeRiment) under international collaboration with ISAS/JAXA, JPL/NASA, Caltech, and so on. We successfully launched CIBER four times, and now we are developing CIBER-2. In addition, I am analyzing data of the infrared diffuse radiation obtained by AKARI, the Japanese infrared satellites. Also, I developed a new method to observe the infrared diffuse radiation by using the Galilean satellites occultation, and I lead an observational program of this method using Subaru telescope, Hubble space telescope, and Spitzer space telescope. Jovian upper atmosphere is also studied as a by-product in this Galilean satellites occultation program.

I also develop instruments for JAXA’s future missions such as the next-generation infrared space telescope SPICA, the infrared spectrometer NIRS3 onboard the next-generation asteroid sample return mission HAYABUSA-2, and the infrared telescope EXZIT onboard the Jovian Trojan mission by a solar-power sail spacecraft.

CIBER 4th flight at NASA Wallops flight facility on 2014/Jun./5th.
Photo: ARAI Toshiaki (ISAS/JAXA)


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