Constraining spatial extent and temperature of dust around galaxies from far-infrared image stacking analysis

TL;DR

This paper introduces a new method combining far-infrared image stacking and quasar reddening measurements to constrain the spatial extent and temperature of dust around galaxies, providing insights into galactic dust properties.

Contribution

The paper presents a novel approach that integrates FIR emission profiles and quasar reddening to estimate dust temperature and distribution around galaxies.

Findings

Estimated dust temperature around 18K with a single-temperature model.

Higher dust temperatures (20K-30K) are implied if additional low-temperature dust components exist.

Current data limitations prevent definitive conclusions about dust distribution and temperature.

Abstract

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 photometric galaxies over the IRAS 100$\mu$m 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 18K, 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 the temperature of the galactic dust needs to be higher, 20K to 30K. 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 multi-band measurement of dust will offer an interesting constraint on the statistical nature of galactic dust.