Near-Infrared Detection of Super-Thin Disks of Massive Spiral Galaxies
American Astronomical Society, AAS Meeting #221, #146.22
Published in Jan 2013
In the Milky Way star formation preferentially occurs close to the galactic midplane, and can be represented by a super-thin disk with an exponential-like radial and vertical profile. Unfortunately, due to dust attenuation, it is not clear if other massive spiral galaxies also possess such disks. Indirect evidence for the presence of such a component comes from the spectral energy distribution of spirals, which contains more far-infrared flux (from dust re-emission) than can be accounted for by an extrapolation of the observed light profile to the midplane. These spectral energy distributions contain no spatial information, however, so the detailed structural parameters of a star-forming disk are not recoverable. We have undertaken a program of high-resolution near-infrared imaging of edge-on spiral galaxies, which, coupled with state-of-the-art radiation transfer models, allow us to strip away the effects of the dust and reveal the intrinsic light distribution all the way down to the midplane. We find that, in addition to thin and thick disks already known from deep optical observations of these galaxies, super-thin disks similar to the Milky Way's are necessary to accurately fit the attenuation-corrected near-infrared light distributions. We acknowledge support for this work from the National Science Foundation (AST-1009491).
(c) 2013: American Astronomical Society