Physics and Astronomy

Associate professor

Nagayama, Takahiro

Exploring the universe with my infrared camera

Infrared astronomical observation

Infrared is an electromagnetic wave that has a wavelength slightly longer than the visible light, and has a characteristic which is less scattered or absorbed by interstellar dust compared to the visible light. The central part of the Milky Way galaxy is actually not seen with the visible light, even if we use the world largest telescope like the Subaru telescope or Hubble Space Telescope.This is due to the heavy extinction effect corresponding to 30 magnitude; the 0th magnitude star becomes 30th magnitude stars. On the other hand, infrared is only attenuated by 3 magnitudes, even when there is an 30 magnitude of extinction in the visible light. It means we can see the central part of Galactic Center much easily by observing in infrared.
We are studying the shape of Milky Way galaxy based on the infrared monitoring observation of Mira variable stars.Mira variables have a special relation between their luminosity and period of brightness variability, and we can estimate their distance from the period obtained by the monitoring of their brightness. In addition, we are also studying the transient phenomena, for example, novae or super novae. Recently, we observed the afterglow radiated by the neutron stars merger which emitted the gravitational wave, and contributed the research which suggests that the heavy elements like Gold or Platinum are formed by the neutron stars merger.

The instrument development by ourself

We have a optical and infrared 1m telescope in Satsuma-Sendai city, 50km north of our university, and we attached an infrared camera on this telescope. We also installed an infrared camera on Nagoya University IRSF 1.4 m telescope located in Republic of South Africa. I involved their development when I was a graduate student in Nagoya University. Infrared cameras for the astronomical observation are not basically commercially available. Also, even if we can buy them, we can only get the similar data as the other researchers can. So we are developing our own infrared cameras in our laboratory to obtain unique data that only we can obtain in the world.
Infrared cameras are products assembled by optics to refocus an infrared image collected by a telescope, detectors and electronic technologies to measure the image on the focal plane with high accuracy, and vacuum and cooling technology to cool optical components and detectors to cryogenic temperature. We are currently developing a new near-infrared 3-band simultaneous imaging camera to be attached to our 1m telescope. The main staff of this camera development is a graduate student.As I myself did so, the development of infrared camera is not easy and requires a lot of struggles, but the pleasure when my instrument achieved the first observation is hard to replace anything. I hope my graduate students experience both the suffering of instrument development and the delight when the development completed.

Profile

Physics and Astronomy

Associate professor

Nagayama, Takahiro

Born in Aichi prefecture in 1975, I obtained PhD of Science from Nagoya University in 2005.
I experienced the post-doctoral researcher at Kyoto University and Nagoya University, and then got the current position at Kagoshima University in April 2014.

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