On surface brightness and flux calibration for point and compact extended sources in the AKARI Far-IR All-Sky Survey (AFASS) maps

PASJ: Publications of the Astronomical Society of Japan

Fullard, Andrew G¹  Ueta, Toshiya¹  Takita, Satoshi²  Szczerba, Ryszard³ 

[1] Department of Physics and Astronomy, University of Denver, 2112 East Wesley Ave., Denver, CO 80208, USA;Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210, Japan;Nicolaus Copernicus Astronomical Centre, PAS, ul. Rabiańska 8, 87-100 Toruń, Poland

关键词: methods: data analysis;    techniques: photometric;    surveys;    techniques: image processing;    atlases;   

DOI  :  10.1093/pasj/psy097

学科分类：天文学(综合)

来源: Oxford University Press

【 摘 要 】

The AKARI infrared astronomical satellite produced all-sky survey (AFASS) maps in the far-infrared at roughly arcminute spatial resolution, enabling us to investigate the whole sky in the far-infrared for objects having surface brightnesses greater than a few to a couple of dozen MJy sr−1. While the AFASS maps are absolutely calibrated against large-scale diffuse emission, it was uncertain whether or not an additional flux correction for point sources was necessary. Here, we verify that calibration for point-source photometry in the AFASS maps is proper. With the aperture correction method based on the empirical point spread function templates derived directly from the AFASS maps, fluxes in the AKARI bright source catalogue (BSC) are reproduced. The AKARI BSC fluxes are also satisfactorily recovered with the 1 σ aperture, which is the empirical equivalent of an infinite aperture. These results confirm that in the AFASS maps far-infrared photometry can be properly performed by using the aperture correction method for point sources and by summing all pixel values within an appropriately defined aperture of the intended target (i.e., the aperture photometry method) for extended sources.

【 授权许可】

CC BY