The AKARI/IRC mid-infrared all-sky survey

Abstract

Context. AKARI is the first Japanese astronomical satellite dedicated to infrared astronomy. One of the main purposes of AKARI is the all-sky survey performed with six infrared bands between 9 μm and 200 μm during the period from 2006 May 6 to 2007 August 28. In this paper, we present the mid-infrared part (9 μm and 18 μm bands) of the survey carried out with one of the on-board instruments, the infrared camera (IRC). Aims. We present unprecedented observational results of the 9 μm and 18 μm AKARI all-sky survey and detail the operation and data processing leading to the point source detection and measurements. Methods. The raw data are processed to produce small images for every scan, and the point sources candidates are derived above the 5σ noise level per single scan. The celestial coordinates and fluxes of the events are determined statistically and the reliability of their detections is secured through multiple detections of the same source within milli-seconds, hours, and months from each other. Results. The sky coverage is more than 90% for both bands. A total of 877 091 sources (851 189 for 9 μm, 195 893 for 18 μm) are confirmed and included in the current release of the point source catalog. The detection limit for point sources is 50 mJy and 90 mJy for the 9 μm and 18 μm bands, respectively. The position accuracy is estimated to be better than 2 . Uncertainties in the in-flight absolute flux calibration are estimated to be 3% for the 9 μm band and 4% for the 18 μm band. The coordinates and fluxes of detected sources in this survey are also compared with those of the IRAS survey and are found to be statistically consistent.

Space-Based Thermal Infrared Studies of Asteroids

“…AKARI's liquid helium supply lasted until August 26, 2007 and enabled 550 days of fully cryogenic operations (the AKARI "cold mission"). During the cold mission phase, AKARI completed an all-sky survey at six bands: 9, 18, 65, 90, 140, and 160 µm (Ishihara et al 2010;Yamamura et al 2010). The mid-IR part of the all-sky survey was conducted at two broad bands centered at 9 and 18 µm with the IRC.…”

“…More than 90% of the sky was observed with both bands, and a large portion of the sky was observed more than three times. The point source catalog of ∼877,000 objects was produced from the mid-IR images of the all-sky survey data (Ishihara et al 2010). An asteroid catalog was also constructed from the mid-IR survey data (Usui et al 2011).…”

A Source Extraction Method for the Akari Mid-Ir Faint Source Catalogue

“…The publicly-available point source catalogue (PSC; Ishihara et al, 2010) contains reliable but relatively bright sources, because point sources were extracted from single scan images. We plan to extract fainter sources by stacking all the scan images.…”

Akari-Fis Point Source Catalogue: Current Status and Future Plan

“…The survey successfully covered more than 96 per cent of the entire sky. The first products from the AKARI All-Sky Survey data were two point source catalogues, namely the FIS Bright Source Catalogue Version 1 (hereafter FIS BSC V1; Yamamura et al, 2010) and the IRC Point Source Catalogue Version 1 (IRC PSC V1; Ishihara et al, 2010). These catalogues were produced and released simultaneously but individually, mainly because the large difference in the spatial resolution made the cross-identification ambiguous.…”