Calibration and performance of the akari far-infrared surveyor (fis) - Slow-scan observation mode for point-sources

Mai Shirahata, Shuji Matsuura, Sunao Hasegawa, Takafumi Ootsubo, Sin'Itirou Makiuti, Issei Yamamura, Takao Nakagawa, Mitsunobu Kawada, Hidehiro Kaneda, Hiroshi Shibai, Yasuo Doi, Toyoaki Suzuki, Thomas Müller, Martin Cohen

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)


We present the characterization and calibration of the Slow-Scan observation mode of the Far-Infrared Surveyor (FIS) onboard the AKARI satellite. The FIS, one of the two focal-plane instruments on AKARI, has four photometric bands between 50-180 μm with two types of Ge:Ga array detectors. In addition to the All-Sky Survey, FIS has also taken detailed far-infrared images of selected targets by using the Slow-Scan mode. The sensitivity of the Slow-Scan mode is one to two orders of magnitude better than that of the All-Sky Survey, because the exposure time on a targeted source is much longer. The point spread functions (PSFs) were obtained by observing several bright point-like objects, such as asteroids, stars, and galaxies. The derived full widths at the half maximum (FWHMs) are ∼30" for the two shorter wavelength bands and ∼40" for the two longer wavelength bands, being consistent with those expected by optical simulation, although a certain amount of excess is seen in the tails of the PSFs. A flux calibration was performed by observations of well-established photometric calibration standards (asteroids and stars) over a wide range of fluxes. After establishing the method of aperture photometry, the photometric accuracy for point-sources is better than ±15% in all of the bands, expect for the longest wavelength.

Original languageEnglish
Pages (from-to)737-750
Number of pages14
JournalPublications of the Astronomical Society of Japan
Issue number4
Publication statusPublished - 2009
Externally publishedYes


  • Instrumentation: detectors
  • Methods: data analysis
  • Space vehicles
  • Techniques: photometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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