Abstract
Using data from the FIS AKARI All-Sky Survey, we make a first step towards the estimation of the contribution from Asymptotic Giant Branch (AGB) stars to the far-infrared (FIR) flux from the Milky Way. We estimate the contribution from the AGB, and post-AGB, stars to the total flux generated by point sources outside the Galactic plane. Additionally, we present the positions of different types of AGB, and post-AGB, stars in the FIR color-color diagrams. Our main conclusion is that there is a high contribution from AGB stars, and particularly post-AGB stars, to the FIR flux coming from point sources in the outer parts of the Milky Way and possibly other Milky Way-type galaxies. FIR colors of different types of AGB stars remain similar but post-AGB stars are redder in the FIR and, as a result, contribute more to the total Galaxy flux density at longer FIR wavelengths.
Highlights
Emission from galaxies at wavelengths longer than a few micrometers is produced mainly by dust
In Pollo et al (2010a), we have examined the effect of photometric errors on the boundary of the star-galaxy classification, and found that this affects the position of the boundary on the color-color plane, but not so significantly that it would change quantitative conclusions
Among all the AKARI Far-Infrared Surveyor (FIS) All-Sky Survey sources, we found 43342 sources with fluxes measured at all four FIR bands
Summary
Emission from galaxies at wavelengths longer than a few micrometers is produced mainly by dust. As is widely known, star-formation activity is always accompanied by dust production on a timescale of 106 yr, very probably through dust production in supernova explosion (e.g., Kozasa and Hasegawa, 1987; Kozasa et al, 1991; Nozawa et al, 2003, 2007, 2008, 2010), though the actual mechanism of dust supply has not been fully understood yet. In such a case, the energy emitted by massive stars in the ultraviolet (UV) is scattered efficiently and absorbed by dust grains. Radiative processes in FIR can be related both to the composition and the amount of dust in galaxies and to the properties of their stellar population, especially the fraction of newly-formed massive stars
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