A dust component 2 kpc above the plane in NGC 891

Abstract

The halo of NGC 891 has been the subject of studies for more than a decade. One of its most striking features is the large asymmetry in H$\alpha$ emission. In this letter, we will take a quantitative look at this asymmetry at different wavelengths for the first time. We suggest that NGC 891 is intrinsically almost symmetric and the large asymmetry in H$\alpha$ emission is mostly due to dust attenuation. We will quantify the additional optical depth needed to cause the observed asymmetry in this model. By comparing large strips on the North East side of the galaxy with strips covering the same area in the South West we can quantify and analyze the asymmetry in the different wavelengths. From the 24 $\mu$m emission we find that the intrinsic asymmetry in star formation in NGC 891 is small i.e., $\sim 30$. The additional asymmetry in H$\alpha$ is modeled as additional symmetric dust attenuation which extends up to $\sim$ 40\arcsec (1.9 kpc) above the plane of the galaxy with a mid-plane value of $\tau$=0.8 and a scale height of 0.5 kpc

A&A in press. 5 pages, 3 figures

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Cited by in corpus (27)

• Galaxy Disks
• High-resolution, 3D radiative transfer modeling : I. The grand-design spiral galaxy M51
• The DiskMass Survey. II. Error Budget
• A resolved analysis of cold dust and gas in the nearby edge-on spiral NGC 891
• An HST/ACS investigation of the spatial and chemical structure and sub-structure of NGC 891, a Milky Way analogue
• Lopsided galaxies: the case of NGC 891
• HALOGAS observations of NGC 5023 and UGC 2082: Modeling of non-cylindrically symmetric gas distributions in edge-on galaxies
• Herschel/SPIRE Observations of the Dusty Disk of NGC 4244
• Diffuse Extraplanar Dust in NGC 891
• HERschel Observations of Edge-on Spirals (HEROES). I: Far-infrared morphology and dust mass determination
• A Multi-Wavelength Infrared Study of NGC 891
• Insights into gas heating and cooling in the disc of NGC 891 from Herschel far-infrared spectroscopy
• The 3-Dimensional Distribution of Dust in NGC 891
• Halo dust detection around NGC 891
• The stellar population content of the thick disk and halo of the Milky Way analogue NGC 891
• HERschel Observations of Edge-on Spirals (HEROES). IV. Dust energy balance problem
• Near-Infrared Detection of a Super-Thin Disk in NGC 891
• SNIa Host Galaxy Properties and the Dust Extinction Distribution
• On the Kinematics of Cold, Metal-enriched Galactic Fountain Flows in Nearby Star-forming Galaxies
• Gaps in the cloud cover? Comparing extinction measures in spiral disks
• The Opacity of Spiral Galaxy Disks VIII: Structure of the Cold ISM
• Host Galaxy Extinction of SNIa: Co-evolution of ISM Structure and Extinction Law with Star-Formation
• Near-Infrared Structure of Fast and Slow Rotating Disk Galaxies
• JWST MIRI and NIRCam observations of NGC 891 and its circumgalactic medium
• Near-Infrared Polarimetry of the Edge-On Galaxy NGC891
• New HErschel Multi-wavelength Extragalactic Survey of Edge-on Spirals (NHEMESES)
• Exploring the Magnetic Field Geometry in NGC 891 with SOFIA/HAWC+