Candidate List of Edge-on Galaxies with Substantial Extraplanar Dust

We present a list of edge-on galaxies that might have substantial extraplanar dust. Twenty-three edge-on galaxies were selected as target galaxies from an edge-on galaxy catalog, and their Galaxy Evolution Explorer far-ultraviolet images were fitted with a three-dimensional radiative transfer galaxy...

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Veröffentlicht in:The Astrophysical journal. Supplement series 2018-12, Vol.239 (2), p.21
1. Verfasser: Shinn, Jong-Ho
Format: Artikel
Sprache:eng
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Zusammenfassung:We present a list of edge-on galaxies that might have substantial extraplanar dust. Twenty-three edge-on galaxies were selected as target galaxies from an edge-on galaxy catalog, and their Galaxy Evolution Explorer far-ultraviolet images were fitted with a three-dimensional radiative transfer galaxy model. The galaxy model is described by two disks: one for the light source and the other for the dust. The best-fit parameters were found by employing a global optimization method called differential evolution. To find the galaxies with substantial extraplanar dust using the best-fit parameters, we plotted the ratio of scale height to galactic diameter: zs/D25,ph (light source) versus zd/D25,ph (dust). We found that 17 and 6 galaxies fall on the region of (zs/D25,ph × 100) >0.2 and (zs/D25,ph × 100) < 0.2, respectively. The former is labeled "high-group" and the latter is labeled "low-group." We conclude that "high-group" galaxies likely have substantial extraplanar dust, while "low-group" galaxies likely have little extraplanar dust, i.e., typical galactic thin disks, based on the following points: (1) the relative positions of "high-group" and "low-group" on the plot zs/D25,ph versus zd/D25,ph with respect to the reference values from optical radiative transfer studies; (2) the lower scale height of the young stellar population than the old stellar population; and (3) a test result that shows the existence of extraplanar dust causes zs and zd to be overestimated in the fitting results. We also examined the dependence of the group separation on the surface density of far-ultraviolet luminosity ( ), but found no strong dependence.
ISSN:0067-0049
1538-4365
DOI:10.3847/1538-4365/aae3e5