Modelling Dust Scattering in our Galaxy

Abstract

I have used Monte Carlo models with multiple scattering to predict the dust scattered light from our Galaxy and have compared the predictions with data in two UV bands from the GALEX spacecraft. I find that 90\% of the scattered light arises from less than 1000 stars with 25\% from the 10 brightest. About half of the diffuse radiation originates within 200 pc of the Sun with a maximum distance of 600 pc. Multiple scattering is important at any optical depth with 30\% of the flux being multiply scattered even at zero reddening. I find that the global distribution of the scattered light is insensitive to the dust distribution with grains of $0.3<a<0.5$ and $g<0.6$. There is an offset between the model and the data of 100 and 200 ph cm${}^{-2}$ s${}^{-1}$ sr${}^{-1}$ Å${}^{-1}$ in the FUV and NUV, respectively, at the poles rising to 200 --- 400 ph cm${}^{-2}$ s${}^{-1}$ sr${}^{-1}$ Å${}^{-1}$ at lower latitudes. The Monte Carlo code and the models of diffuse radiation for different values of the optical constants are available for download.

12 pages, 19 figures

References in corpus (9)

• Astrophysics Source Code Library
• New Grids of ATLAS9 Model Atmospheres
• A Three-Dimensional Map of Milky-Way Dust
• The Spectroscopy of Plasma Evolution from Astrophysical Radiation Mission
• GALEX Diffuse Observations of the Sky: The Data
• The Mystery of the Cosmic Diffuse Ultraviolet Background Radiation
• Diffuse Far-ultraviolet Observations of the Taurus Region
• Measurement of Dust Optical Properties in Coalsack
• Diffuse Radiation from the Aquila Rift

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• Components of the Diffuse Ultraviolet Radiation at High Latitudes
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• Joint Modelling of Dust Scattering and Thermal Emission: The Spider Complex
• Galactic Latitude Dependence of Near-Infrared Diffuse Galactic Light : Thermal Emission or Scattered Light?
• Astrophysics with New Horizons: Making the Most of a Generational Opportunity
• Evidence for large-scale excesses associated with low HI column densities in the sky I. Dust excess
• Optical and UV surface brightness of translucent dark nebulae: Dust albedo, radiation field and fluorescence emission by H2
• Galaxy Cluster Contribution to the Diffuse Extragalactic Ultraviolet Background
• Excess Ultraviolet Emission at High Galactic Latitudes: A New Horizons View
• Dust Scattering from the Taurus Molecular Cloud
• Dust Scattered Radiation in the Galactic Poles
• Constraining $z\lesssim 2$ ultraviolet emission with the upcoming ULTRASAT satellite
• Probing the infrared counterparts of diffuse far-ultraviolet sources in the Galaxy
• Construction of a far ultraviolet all sky map from an incomplete survey: Application of a deep learning algorithm
• A Monte Carlo Implementation of Galactic Free-Free Emission for the EoR Foreground Models