The Astrophysical Journal, vol. 857, no. 1, pp. 37(11pp)

Authors:

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

URL:

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 hertz. 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.