Fast radio bursts by stellar wind microlensing of a faint background source
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| Format: | Preprint |
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2025
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| _version_ | 1866912527080751104 |
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| author | Lieu, Richard |
| author_facet | Lieu, Richard |
| contents | By assuming the inverse square law of solar wind plasma density as representative of other stars, it is shown that just outside a star the {\it outward} deflection of a passing radio signal at $ν\approx 1$~GHz (which is capable of penetrating the plasma) is about 5 times larger than the gravitational inward deflection by the star, and the ensuing lens equation which takes both effects into account is a cubic polynomial with three roots and a new strong lensing caustic. The geometric optics approach is valid for a radio source size $\lesssim 1$~pc. Microlensing magnification of a steady background source occurs typically over a timescale of milliseconds, resulting in $\approx 80$ Fast Radio Bursts (FRBs) per day over the whole sky, which can only perturb the isotropy of FRB distribution at the several \% level. Moreover, repeating FRBs could be triggered by the periodic interception of the line-of-sight of the background source by members of a binary system. The temporal signatures of such FRBs are consistent with the power spectrum of solar wind density fluctuations on corresponding scales, except the mean density of the wind is a few times higher than the solar value. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2508_05947 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Fast radio bursts by stellar wind microlensing of a faint background source Lieu, Richard High Energy Astrophysical Phenomena General Relativity and Quantum Cosmology High Energy Physics - Theory By assuming the inverse square law of solar wind plasma density as representative of other stars, it is shown that just outside a star the {\it outward} deflection of a passing radio signal at $ν\approx 1$~GHz (which is capable of penetrating the plasma) is about 5 times larger than the gravitational inward deflection by the star, and the ensuing lens equation which takes both effects into account is a cubic polynomial with three roots and a new strong lensing caustic. The geometric optics approach is valid for a radio source size $\lesssim 1$~pc. Microlensing magnification of a steady background source occurs typically over a timescale of milliseconds, resulting in $\approx 80$ Fast Radio Bursts (FRBs) per day over the whole sky, which can only perturb the isotropy of FRB distribution at the several \% level. Moreover, repeating FRBs could be triggered by the periodic interception of the line-of-sight of the background source by members of a binary system. The temporal signatures of such FRBs are consistent with the power spectrum of solar wind density fluctuations on corresponding scales, except the mean density of the wind is a few times higher than the solar value. |
| title | Fast radio bursts by stellar wind microlensing of a faint background source |
| topic | High Energy Astrophysical Phenomena General Relativity and Quantum Cosmology High Energy Physics - Theory |
| url | https://arxiv.org/abs/2508.05947 |