Curvature-Radiation Geometries Across the Second CHIME/FRB Fast Radio Burst Population
Abstract
We present a population-level spectral analysis of fast radio bursts from the second CHIME/FRB catalog using three curvature-radiation-motivated templates: point-source, one-dimensional bunch, and paired-bunch cavity models. Fits are evaluated with reduced chi-squared χ2r, AIC/BIC, and the Ljung-Box residual autocorrelation test. All three templates yield median χ2r values close to unity for both repeating and non-repeating bursts. Repeaters show narrower χ2r distributions than non-repeaters, with statistically significant but modest population-level differences. AIC favours the one-dimensional bunch model for the largest fraction of sources, whereas BIC increases the relative preference for the simpler point-source model. However, residual autocorrelation remains widespread across all models: only 15%-21% of sources simultaneously satisfy goodness-of-fit and residual-independence criteria, indicating persistent structured residuals beyond the tested templates. These results suggest that while curvature-radiation-motivated geometries capture the dominant spectral envelope of many FRBs, additional physical ingredients or spectral components are required to describe the fine-scale spectral structure of the data. The inferred coherence scales are ∼16-18 cm for the one-dimensional model and ∼25-28 cm for the cavity model.
Versions
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BibTeX
@misc{alencar2026curvatureradiation,
title = {{Curvature-Radiation Geometries Across the Second CHIME/FRB Fast Radio Burst Population}},
author = {Thonimar V. Alencar and Jéferson A. S. Fortunato and Wiliam S. Hipólito-Ricaldi},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2606.17039},
eprint = {2606.17039},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.17039},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Curvature-Radiation Geometries Across the Second CHIME/FRB Fast Radio Burst Population
AU - Thonimar V. Alencar
AU - Jéferson A. S. Fortunato
AU - Wiliam S. Hipólito-Ricaldi
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2606.17039
UR - https://arxiv.org/abs/2606.17039
AB - We present a population-level spectral analysis of fast radio bursts from the second CHIME/FRB catalog using three curvature-radiation-motivated templates: point-source, one-dimensional bunch, and paired-bunch cavity models. Fits are evaluated with reduced chi-squared χ^2_r, AIC/BIC, and the Ljung-Box residual autocorrelation test. All three templates yield median χ^2_r values close to unity for both repeating and non-repeating bursts. Repeaters show narrower χ^2_r distributions than non-repeaters, with statistically significant but modest population-level differences. AIC favours the one-dimensional bunch model for the largest fraction of sources, whereas BIC increases the relative preference for the simpler point-source model. However, residual autocorrelation remains widespread across all models: only 15%-21% of sources simultaneously satisfy goodness-of-fit and residual-independence criteria, indicating persistent structured residuals beyond the tested templates. These results suggest that while curvature-radiation-motivated geometries capture the dominant spectral envelope of many FRBs, additional physical ingredients or spectral components are required to describe the fine-scale spectral structure of the data. The inferred coherence scales are ∼16-18 cm for the one-dimensional model and ∼25-28 cm for the cavity model.
ER -