DIFFUSE EXTRAPLANAR DUST IN NGC 891

We report the detection of vertically extended far-ultraviolet and near-UV emissions in an edge-on spiral galaxy NGC 891, which we interpret as being due to dust-scattered starlight. Three-dimensional radiative transfer models are used to investigate the content of the extraplanar dust that is requi...

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Bibliographic Details
Published in:Astrophysical journal. Letters 2014-04, Vol.785 (1), p.1-6
Main Authors: Seon, Kwang-Il, Witt, Adolf N, Shinn, Jong-Ho, Kim, Il-Joong
Format: Article
Language:English
Subjects:
Approximation
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
COSMIC DUST
DETECTION
Disks
Dust
FAR ULTRAVIOLET RADIATION
GALAXIES
LAYERS
MASS
PHOTON EMISSION
RADIANT HEAT TRANSFER
Radiative transfer
SCALE HEIGHT
Texts
Three dimensional models
THREE-DIMENSIONAL CALCULATIONS
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Summary:We report the detection of vertically extended far-ultraviolet and near-UV emissions in an edge-on spiral galaxy NGC 891, which we interpret as being due to dust-scattered starlight. Three-dimensional radiative transfer models are used to investigate the content of the extraplanar dust that is required to explain the UV emission. The UV halos are well reproduced by a radiative transfer model with two exponential dust disks, one with a scale height of [approximate]0.2-0.25 kpc and the other with a scale height of [approximate]1.2-2.0 kpc. The central face-on optical depth of the geometrically thick disk is found to be (ProQuest: Formulae and/or non-USASCII text omitted) [approximate] 0.3-0.5 at the B band. The results indicate that the dust mass at z > 2 kpc is [approximate]3%-5% of the total dust mass, which is in good accordance with the recent Herschel submillimeter observation. Our results, together with the recent discovery of the UV halos in other edge-on galaxies, suggest the widespread existence of a geometrically thick dust layer above the galactic plane in spirals.
ISSN:2041-8205
2041-8213
DOI:10.1088/2041-8205/785/1/L18