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Title: NEAR-INFRARED DETECTION OF A SUPER-THIN DISK IN NGC 891

We probe the disk structure of the nearby, massive, edge-on spiral galaxy NGC 891 with subarcsecond resolution JHK{sub s}-band images covering {approx} {+-}10 kpc in radius and {+-}5 kpc in height. We measure intrinsic surface brightness (SB) profiles using realistic attenuation corrections constrained from near- and mid-infrared (Spitzer) color maps and three-dimensional Monte Carlo radiative-transfer models. In addition to the well-known thin and thick disks, a super-thin disk with 60-80 pc scale-height-comparable to the star-forming disk of the Milky Way-is visibly evident and required to fit the attenuation-corrected light distribution. Asymmetries in the super-thin disk light profile are indicative of young, hot stars producing regions of excess luminosity and bluer (attenuation-corrected) near-infrared color. To fit the inner regions of NGC 891, these disks must be truncated within {approx}3 kpc, with almost all their luminosity redistributed in a bar-like structure 50% thicker than the thin disk. There appears to be no classical bulge but rather a nuclear continuation of the super-thin disk. The super-thin, thin, thick, and bar components contribute roughly 30%, 42%, 13%, and 15% (respectively) to the total K{sub s}-band luminosity. Disk axial ratios (length/height) decrease from 30 to 3 from super-thin to thick components. Both exponential and sech{supmore » 2} vertical SB profiles fit the data equally well. We find that the super-thin disk is significantly brighter in the K{sub s}-band than typically assumed in integrated spectral energy distribution models of NGC 891: it appears that in these models the excess flux, likely produced by young stars in the super-thin disk, has been mistakenly attributed to the thin disk.« less
Authors:
;  [1]
  1. Department of Astronomy, University of Wisconsin, 475 N. Charter Street, Madison, WI 53706 (United States)
Publication Date:
OSTI Identifier:
22140259
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 773; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASYMMETRY; ATTENUATION; AXIAL RATIO; BRIGHTNESS; COLOR; DISTRIBUTION; ENERGY SPECTRA; GALAXIES; LUMINOSITY; MILKY WAY; MONTE CARLO METHOD; PHOTOMETRY; RADIANT HEAT TRANSFER; SURFACES; THREE-DIMENSIONAL CALCULATIONS; VISIBLE RADIATION