ISOPHOT Maps of NGC 6946 in the range λ 60-200µm.
Helou, G.; Lemke, D.; Gabriel, C.; Heinrichsen, I.; Hippelein, H.; Tuffs, R. J.; Xu, C.; Lu, N. Y.; Davies, J. I.; Skaley, D.
Abstract
We present maps of NGC 6946 at λ 61 and 205μm as well as scans through the galaxy at these and at 8 intermediate wavelengths. The bulk of the FIR luminosity arises from a diffuse disk component which extends beyond the 25mag/arcsec^2^ B isophote to at least the radius corresponding to the sensitivity limit. A FIR emission counterpart to the outlying HI disk is seen at both 61 and 205μm, for which a dust to HI mass ratio of 0.0046 is inferred from the 205μm brightness assuming a dust temperature of 15K. The disk scale length at both λ 61 and 205μm is similar to that seen in R-band.