Time-Domain Dust Astrophysics. I. Polarization Flares, Polarization-Angle Reverberation, and Fossil Imprints in Supernova-Illuminated Clouds
Abstract
Cosmic transients can enhance the local radiation field on timescales of days to months. Using the time-domain \TransRAT\ framework, which self-consistently follows grain heating, alignment, rotational disruption, and switching of the alignment axis between the magnetic field ({\bf B}) and the radiation direction ({\bf k}), we predict the time-dependent dust polarization of a dense cloud, represented by a homogeneous one-zone model, illuminated by a Type~IIP supernova over a range of source--cloud distances. We identify four key signatures. First, for D≲1~pc, a \emph{polarization flare} develops within days to weeks, marked by sharp increases in both thermal dust polarization and extinction-polarization efficiency; this is followed by a \emph{polarization dip} as radiative torque disruption (RAT-D) destroys the large aligned grains. Second, the peak wavelength of extinction polarization, λmax, shifts blueward as the minimum aligned-grain size decreases. Third, the transition from B-RAT to k-RAT produces an abrupt \emph{polarization-angle rotation} of up to 45∘ in our fiducial geometry. Fourth, as the transient fades, the return to B-RAT generates a \emph{polarization-angle reverberation} governed by Larmor precession. At D>1~pc, SN-induced polarization properties can persist long after the radiation has faded. These {\it fossil imprints} offer the most practical near-term observational test: clouds near supernova remnants younger than the relaxation timescale of ∼10 tgas with tgas gas damping time, should exhibit elevated polarization and blueshifted λmax today. Time-dependent dust polarization can therefore probe dust physics, dust properties, and pristine pre-shock magnetic fields in real time, while fossil imprints preserve a record of past explosions.
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BibTeX
@misc{hoang2026timedomain,
title = {{Time-Domain Dust Astrophysics. I. Polarization Flares, Polarization-Angle Reverberation, and Fossil Imprints in Supernova-Illuminated Clouds}},
author = {Thiem Hoang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2607.24517},
eprint = {2607.24517},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.24517},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Time-Domain Dust Astrophysics. I. Polarization Flares, Polarization-Angle Reverberation, and Fossil Imprints in Supernova-Illuminated Clouds
AU - Thiem Hoang
PY - 2026
DA - 2026/09/11
PB - arXiv
DO - 10.48550/arxiv.2607.24517
UR - https://arxiv.org/abs/2607.24517
AB - Cosmic transients can enhance the local radiation field on timescales of days to months. Using the time-domain \TransRAT\ framework, which self-consistently follows grain heating, alignment, rotational disruption, and switching of the alignment axis between the magnetic field ({\bf B}) and the radiation direction ({\bf k}), we predict the time-dependent dust polarization of a dense cloud, represented by a homogeneous one-zone model, illuminated by a Type~IIP supernova over a range of source--cloud distances. We identify four key signatures. First, for D≲1~pc, a \emph{polarization flare} develops within days to weeks, marked by sharp increases in both thermal dust polarization and extinction-polarization efficiency; this is followed by a \emph{polarization dip} as radiative torque disruption (RAT-D) destroys the large aligned grains. Second, the peak wavelength of extinction polarization, λ_max, shifts blueward as the minimum aligned-grain size decreases. Third, the transition from B-RAT to k-RAT produces an abrupt \emph{polarization-angle rotation} of up to 45^∘ in our fiducial geometry. Fourth, as the transient fades, the return to B-RAT generates a \emph{polarization-angle reverberation} governed by Larmor precession. At D>1~pc, SN-induced polarization properties can persist long after the radiation has faded. These {\it fossil imprints} offer the most practical near-term observational test: clouds near supernova remnants younger than the relaxation timescale of ∼10 t_gas with t_gas gas damping time, should exhibit elevated polarization and blueshifted λ_max today. Time-dependent dust polarization can therefore probe dust physics, dust properties, and pristine pre-shock magnetic fields in real time, while fossil imprints preserve a record of past explosions.
ER -