Deep Submillimeter Images of NGC 891—Cold Dust at Larger Galactic Radii

TLDR

These measurements, carried out with the recently commissioned Submillimeter Common‑User Bolometer Array, provide the deepest images yet of a nearby galaxy in the submillimeter wave band. We present 450 and 850 μm continuum images of the edge‑on galaxy NGC 891. The observations were made with the Submillimeter Common‑User Bolometer Array. We detect dust emission across two‑thirds of the optical disk, including chimneys extending up to ~2 kpc, and find that cold (~15 K) dust dominates the disk, comprising an order of magnitude more mass than warm dust and being especially abundant at larger galactic radii.

Abstract

We present images in the 450 and 850 μm continuum of the edge-on galaxy NGC 891. These measurements, carried out with the recently commissioned Submillimeter Common-User Bolometer Array, provide the deepest images yet of a nearby galaxy in the submillimeter wave band. We detect dust emission from 2/3 of the optical disk and confirm the presence of dust chimneys escaping from the main absorption layer up to z-heights of nearly 2 kpc. A comparison between the submillimeter surface brightness along the major axis with that corresponding to the IRAS 60 and 100 μm filters implies that large amounts of cold dust (~15 K) are present in the disk (in fact, an order of magnitude more grain material than the warm dust detected by IRAS). These cold grains predominate at larger galactic radii.