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arXiv · 1804.04271

"Slow-Scanning" in Ground-Based Mid-Infrared Observation

Ryou Ohsawa·Shigeyuki Sako·Takashi Miyata·Takafumi Kamizuka·Kazushi Okada·Kiyoshi Mori·Masahito S. Uchiyama·Junpei Yamaguchi·Takuya Fujiyoshi·Mikio Morii·Shiro Ikeda
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Abstract

Chopping observations with a tip-tilt secondary mirror have conventionally been used in ground-based mid-infrared observations. However, it is not practical for next generation large telescopes to have a large tip-tilt mirror that moves at a frequency larger than a few Hz. We propose an alternative observing method, a "slow-scanning" observation. Images are continuously captured as movie data, while the field-of-view is slowly moved. The signal from an astronomical object is extracted from the movie data by a low-rank and sparse matrix decomposition. The performance of the "slow-scanning" observation was tested in an experimental observation with Subaru/COMICS. The quality of a resultant image in the "slow-scanning" observation was as good as in a conventional chopping observation with COMICS, at least for a bright point-source object. The observational efficiency in the "slow-scanning" observation was better than that in the chopping observation. The results suggest that the "slow-scanning" observation can be a competitive method for the Subaru telescope and be of potential interest to other ground-based facilities to avoid chopping.

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Ryou Ohsawa, Shigeyuki Sako, Takashi Miyata, Takafumi Kamizuka, Kazushi Okada, Kiyoshi Mori, Masahito S. Uchiyama, Junpei Yamaguchi, Takuya Fujiyoshi, Mikio Morii, Shiro Ikeda. 2018-04-12. "Slow-Scanning" in Ground-Based Mid-Infrared Observation. https://doi.org/10.3847/1538-4357%2Faab6ae

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