The influence of free-free absorption on the radio spectrum of Particle-Accelerating Colliding-Wind Binaries
Abstract
The study of massive stars in binary and higher-multiplicity systems that participate in particle acceleration is a key topic at the crossroads of massive star physics, shock physics, and galactic cosmic ray astrophysics. From an observational perspective, radio measurements are our pri- mary tool for identifying these systems through their synchrotron radio emission. Out of the 54 such systems known to date, all but two have been discovered via their non-thermal radio emission. However, identifying these systems is not straightforward. The main challenge lies in free-free absorption, which can obscure the synchrotron signature and hinder detection. This paper summarizes recent developments in our understanding of these systems, with a particular focus on the strong observational bias introduced by free-free absorption. This bias significantly limits our ability to determine the true fraction of particle accelerators among colliding-wind binaries.
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BibTeX
@misc{becker2026influence,
title = {{The influence of free-free absorption on the radio spectrum of Particle-Accelerating Colliding-Wind Binaries}},
author = {Michaël De Becker and Agustina Belen Blanco and Mathilde Tasseroul and Anandmayee Tej and Anindya Saha and Paula Benaglia and Santiago del Palacio},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.12907},
eprint = {2609.12907},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.12907},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The influence of free-free absorption on the radio spectrum of Particle-Accelerating Colliding-Wind Binaries
AU - Michaël De Becker
AU - Agustina Belen Blanco
AU - Mathilde Tasseroul
AU - Anandmayee Tej
AU - Anindya Saha
AU - Paula Benaglia
AU - Santiago del Palacio
PY - 2026
DA - 2026/09/11
PB - arXiv
DO - 10.48550/arxiv.2609.12907
UR - https://arxiv.org/abs/2609.12907
AB - The study of massive stars in binary and higher-multiplicity systems that participate in particle acceleration is a key topic at the crossroads of massive star physics, shock physics, and galactic cosmic ray astrophysics. From an observational perspective, radio measurements are our pri- mary tool for identifying these systems through their synchrotron radio emission. Out of the 54 such systems known to date, all but two have been discovered via their non-thermal radio emission. However, identifying these systems is not straightforward. The main challenge lies in free-free absorption, which can obscure the synchrotron signature and hinder detection. This paper summarizes recent developments in our understanding of these systems, with a particular focus on the strong observational bias introduced by free-free absorption. This bias significantly limits our ability to determine the true fraction of particle accelerators among colliding-wind binaries.
ER -