AKARI Detection of Far-Infrared Dust Emission in the Halo of NGC253

TL;DR

This study uses AKARI far-infrared images to detect extended dust emission in NGC253's halo, revealing outflowing dust likely heated by superwinds and indicating additional heating sources far from the galaxy disk.

Contribution

First detection of extended FIR dust emission in NGC253's halo, linking it to superwind outflows and suggesting complex dust heating mechanisms.

Findings

FIR dust emission extends up to 9 kpc from the disk.

Dust temperature increases with distance from the galaxy disk.

Halo dust is likely entrained by superwinds.

Abstract

We present new far-infrared (FIR) images of the edge-on starburst galaxy NGC253 obtained with the Far-Infrared Surveyor (FIS) onboard AKARI at wavelengths of 90 um and 140 um. We have clearly detected FIR dust emission extended in the halo of the galaxy; there are two filamentary emission structures extending from the galactic disk up to 9 kpc in the northern and 6 kpc in the northwestern direction. From its spatial coincidence with the X-ray plasma outflow, the extended FIR emission is very likely to represent outflowing dust entrained by superwinds. The ratios of surface brightness at 90 um to that at 140 um suggest that the temperatures of the dust in the halo are getting higher in the regions far from the disk, implying that there exist extra dust heating sources in the halo of the galaxy.