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

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.