Image Stacking Analysis of SDSS Galaxies with AKARI Far-Infrared Surveyor Maps at 65{\mu}m, 90{\mu}m, and 140{\mu}m

TL;DR

This study uses image stacking of SDSS galaxies on AKARI FIR maps to analyze their infrared emission, clustering, and dust temperature, revealing insights into galaxy FIR properties and their dependence on galaxy morphology.

Contribution

It introduces a method to decompose FIR emission into galaxy and clustering components and derives average dust temperatures from stacked galaxy data.

Findings

Mean FIR flux depends on galaxy magnitude as fitted by a specific exponential relation.

Clustering FIR amplitude aligns with galaxy angular correlation, with morphology effects noted.

Derived dust temperature of ~30K matches known FIR luminous galaxy temperatures.

Abstract

We perform image stacking analysis of Sloan Digital Sky Survey (SDSS) photometric galaxies over the AKARI Far-Infrared Surveyor (FIS) maps at 65{\mu}m, 90{\mu}m, and 140{\mu}m. The resulting image profiles are decomposed into the central galaxy component (single term) and the nearby galaxy component (clustering term), as a function of the r-band magnitude, m_r of the central galaxy. We find that the mean far-infrared (FIR) flux of a galaxy with magnitude m_r is well fitted with f^s_{90{\mu}m}=13*10^{0.306(18-m_r)}[mJy]. The FIR amplitude of the clustering term is consistent with that expected from the angular-correlation function of the SDSS galaxies, but galaxy morphology dependence needs to be taken into account for a more quantitative conclusion. We also fit the spectral energy distribution of stacked galaxies at 65{\mu}m, 90{\mu}m, and 140{\mu}m, and derive a mean dust temperature of ~30K. This is consistent with the typical dust temperature of galaxies that are FIR luminous and individually detected.