2015MNRAS.451.4162K

We propose a novel method to constrain the spatial extent of dust around galaxies through the measurement of dust temperature. Our method combines the dust emission of galaxies from far-infrared (FIR) image stacking analysis and the quasar reddening due to the dust absorption around galaxies. As a specific application of our method, we use the stacked FIR emission profiles of SDSS (Sloan Digital Sky Survey) photometric galaxies over the IRAS 100µm map, and the recent measurement of the SDSS galaxy-quasar cross-correlation. If we adopt a single-temperature dust model, the resulting temperature is around 18 K, which is consistent with a typical dust temperature for a central part of galaxies. If we assume an additional dust component with much lower temperature, the current data imply that the temperature of the galactic dust needs to be higher, 20-30 K. Since the model of the density and temperature distribution of dust adopted in the current paper is very simple, we cannot draw any strong conclusion at this point. Nevertheless, our novel method with the elaborated theoretical model and multiband measurement of dust will offer an interesting constraint on the statistical nature of galactic dust.