The extent of dust in NGC 891 from Herschel/SPIRE images

TL;DR

This study uses Herschel/SPIRE images and radiative transfer modeling to analyze the dust distribution in NGC 891, revealing a radial fall-off with a break at 12 kpc and extended emission linked to the HI disk.

Contribution

It provides detailed characterization of the dust distribution and confirms the presence of a dust disk with a break, extending previous infrared observations.

Findings

Dust radial profile shows a break at 12 kpc.

Extended dust emission associated with the HI disk.

No excess dust emission detected above the galactic plane.

Abstract

We analyse Herschel/SPIRE images of the edge-on spiral galaxy NGC 891 at 250, 350 and 500 micron. Using a 3D radiative transfer model we confirm that the dust has a radial fall-off similar to the stellar disk. The dust disk shows a break at about 12 kpc from the center, where the profile becomes steeper. Beyond this break, emission can be traced up to 90% of the optical disk in the NE side. On the SW, we confirm dust emission associated with the extended, asymmetric HI disk, previously detected by the Infrared Space Observatory (ISO). This emission is marginally consistent with the large diffuse dust disk inferred from radiative transfer fits to optical images. No excess emission is found above the plane beyond that of the thin, unresolved, disk.