Year: 2017
Type: article
Abstract: The spatial distribution of dust in galaxies affects the global attenuation, and hence inferred properties, of galaxies. We trace the spatial distribution of dust in five approximately kiloparsec fields of M31 by comparing optical attenuation with the total dust mass distribution. We measure the attenuation from the Balmer decrement using Integral Field Spectroscopy and the dust mass from Herschel far-IR observations. Our results show that M31's dust attenuation closely follows a foreground screen model, contrary to what was previously found in other nearby galaxies. By smoothing the M31 data, we find that spatial resolution is not the cause for this difference. Based on the emission-line ratios and two simple models, we conclude that previous models of dust/gas geometry need to include a weakly or non-attenuated diffuse ionized gas (DIG) component. Due to the variation of dust and DIG scale heights with galactic radius, we conclude that different locations in galaxies will have different vertical distributions of gas and dust and therefore different measured attenuation. The difference between our result in M31 with that found in other nearby galaxies can be explained by our fields in M31 lying at larger galactic radii than the previous studies that focused on the centers of galaxies.
Source: The Astrophysical Journal
Authors: Neven Tomičić, Kathryn Kreckel, Brent Groves, Eva Schinnerer, Karin Sandstrom, Maria Kapala, Guillermo A. Blanc, Adam Leroy
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: National Aeronautics and Space Administration, California Institute of Technology, Imperial College London, Cardiff University, Centre National d’Etudes Spatiales, KU Leuven, Centre National de la Recherche Scientifique, Bundesministerium für Verkehr, Innovation und Technologie, Max-Planck-Institut für Astronomie, Science and Technology Facilities Council, National Astronomical Observatories, Chinese Academy of Sciences
OpenAlex ID: W2695710806