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arXiv · 0904.3788

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 Muller·Martin Cohen
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Abstract

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 um 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 the optical simulation, although a certain amount of excess is seen in the tails of the PSFs. The flux calibration has been performed by the observations of well-established photometric calibration standards (asteroids and stars) in 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.

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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 Muller, Martin Cohen. 2009-04-24. Calibration and Performance of the AKARI Far-Infrared Surveyor (FIS) -- Slow-Scan Observation Mode for Point Sources. https://doi.org/10.1093/pasj%2F61.4.737

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