TY - JOUR
T1 - The Astrodust+PAH Model
T2 - A Unified Description of the Extinction, Emission, and Polarization from Dust in the Diffuse Interstellar Medium
AU - Hensley, Brandon S.
AU - Draine, B. T.
N1 - Funding Information:
We thank the anonymous referee and Simone Bianchi for helpful comments that improved this manuscript. BSH acknowledges support from the NASA TCAN grant No. NNH17ZDA001N-TCAN and, during the earliest stages of this study, a National Science Foundation Graduate Research Fellowship under grant No. DGE-0646086. This research was supported in part by NSF Grant AST-1908123. This research was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
Publisher Copyright:
© 2023. The Author(s). Published by the American Astronomical Society.
PY - 2023/5/1
Y1 - 2023/5/1
N2 - We present a new model of interstellar dust in which large grains are a single composite material, “astrodust,” and nanoparticle-sized grains come in distinct varieties including polycyclic aromatic hydrocarbons (PAHs). We argue that a single-composition model for grains larger than ∼0.02 μm most naturally explains the lack of frequency dependence in the far-infrared (FIR) polarization fraction and the characteristic ratio of optical to FIR polarization. We derive a size distribution and alignment function for 1.4:1 oblate astrodust grains that, with PAHs, reproduce the mean wavelength dependence and polarization of Galactic extinction and emission from the diffuse interstellar medium while respecting constraints on solid-phase abundances. All model data and Python-based interfaces are made publicly available.
AB - We present a new model of interstellar dust in which large grains are a single composite material, “astrodust,” and nanoparticle-sized grains come in distinct varieties including polycyclic aromatic hydrocarbons (PAHs). We argue that a single-composition model for grains larger than ∼0.02 μm most naturally explains the lack of frequency dependence in the far-infrared (FIR) polarization fraction and the characteristic ratio of optical to FIR polarization. We derive a size distribution and alignment function for 1.4:1 oblate astrodust grains that, with PAHs, reproduce the mean wavelength dependence and polarization of Galactic extinction and emission from the diffuse interstellar medium while respecting constraints on solid-phase abundances. All model data and Python-based interfaces are made publicly available.
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U2 - 10.3847/1538-4357/acc4c2
DO - 10.3847/1538-4357/acc4c2
M3 - Article
AN - SCOPUS:85158022218
SN - 0004-637X
VL - 948
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 55
ER -