Determining the extragalactic extinction law with SALT
Abstract
We present CCD imaging observations of early-type galaxies with dark lanes obtained with the Southern African Large Telescope (SALT) during its performance-verification phase. We derive the extinction law by the extragalactic dust in the dark lanes in the spectral range 1.11mu m^{-1} < lambda^{-1} < 2.94 mu m^{-1} by fitting model galaxies to the unextinguished parts of the image, and subtracting from these the actual images. We find that the extinction curves run parallel to the Galactic extinction curve, which implies that the properties of dust in the extragalactic enviroment are similar to those of the Milky Way. The ratio of the total V band extinction to the selective extinction between the V and B bands is derived for each galaxy with an average of 2.82+-0.38, compared to a canonical value of 3.1 for the Milky Way. The similar values imply that galaxies with well-defined dark lanes have characteristic dust grain sizes similar to those of Galactic dust.
Keywords
Cite
@article{arxiv.0808.0714,
title = {Determining the extragalactic extinction law with SALT},
author = {Ido Finkelman and Noah Brosch and Alexei Y. Kniazev and David Buckley and Darragh O'Donoghue and Yas Hashimoto and Nicola Loaring and Encarni Romero and Martin Still and Petri Vaisanen},
journal= {arXiv preprint arXiv:0808.0714},
year = {2014}
}
Comments
20 pages, 15 figures and 4 tables. Accepted for publication in MNRAS