Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Modeling of the ALMA HL Tau Polarization by Mixture of Grain Alignment
  and Self-scattering   Dust polarization at (sub)millimeter wavelengths has been observed for many
protoplanetary disks. Theoretically, multiple origins potentially contribute to
the polarized emission but it is still uncertain what mechanism is dominant in
disk millimeter polarization. To quantitatively address the origin, we perform
radiative transfer calculations of the mixture of alignment and self-scattering
induced polarization to reproduce the 3.1 mm polarization of the HL Tau disk,
which shows azimuthal pattern in polarization vectors. We find that a mixture
of the grain alignment and self-scattering is essential to reproduce the HL Tau
3.1 mm polarization properties. Our model shows that the polarization of the HL
Tau at 3.1 mm can be decomposed to be the combination of the self-scattering
parallel to the minor axis and the alignment-induced polarization parallel to
the major axis, with the orders of $\sim 0.5\%$ fraction for each component.
This slightly eases the tight constraints on the grain size of $\sim
70~{\rm~\mu m}$ to be $\sim 130 {\rm~\mu m}$ in the previous studies but
further modeling is needed. In addition, the grain alignment model requires
effectively prolate grains but the physics to reproduce it in protoplanetary
disks is still a mystery.

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The categories of this paper are: cond-mat
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The categories of this paper are: nucl-th
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The categories of this paper are: ao-sci
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The categories of this paper are: physics
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-th
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The categories of this paper are: hep-ph
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The categories of this paper are: solv-int
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The categories of this paper are: cs
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The categories of this paper are: atom-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: q-fin
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The categories of this paper are: patt-sol
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The categories of this paper are: funct-an
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The categories of this paper are: eess
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The categories of this paper are: q-alg