A possible wave-optical effect in lensed FRBs

Fuente: arXiv
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Main Authors: Sathyanathan, Goureesankar, Leung, Calvin, Wucknitz, Olaf, Saha, Prasenjit
Format: Preprint
Published: 2025
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author Sathyanathan, Goureesankar
Leung, Calvin
Wucknitz, Olaf
Saha, Prasenjit
author_facet Sathyanathan, Goureesankar
Leung, Calvin
Wucknitz, Olaf
Saha, Prasenjit
contents Context: Fast Radio Bursts (FRBs) are enigmatic extragalactic bursts whose properties are still largely unknown, but based on their extremely small time duration, they are proposed to have a compact structure, making them candidates for wave-optical effects if gravitational lensed. If an FRB is lensed into multiple-images bursts at different times by a galaxy or cluster, a likely scenario is that only one image is detected, because the others fall outside the survey area and time frame. Aims: In this work we explore the FRB analog of quasar microlensing, namely the collective microlensing by stars in the lensing galaxy, now with wave optics included. The eikonal regime is applicable here. Methods. We study the voltage (rather than the intensity) in a simple simulation consisting of (a) microlensing stars, and (b) plasma scattering by a turbulent interstellar medium. Results: The auto-correlation of the voltage shows peaks (at order-microsecond separations) corresponding to wave-optical interference between lensed micro-images. The peaks are frequency dependent if plasma-scattering is significant. While qualitative and still in need of more realistic simulations, the results suggest that a strongly-lensed FRB could be identified from a single image. Conclusions: Microlensing could sniff out macro-lensed FRBs
format Preprint
id arxiv_https___arxiv_org_abs_2504_10523
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A possible wave-optical effect in lensed FRBs
Sathyanathan, Goureesankar
Leung, Calvin
Wucknitz, Olaf
Saha, Prasenjit
High Energy Astrophysical Phenomena
Cosmology and Nongalactic Astrophysics
Context: Fast Radio Bursts (FRBs) are enigmatic extragalactic bursts whose properties are still largely unknown, but based on their extremely small time duration, they are proposed to have a compact structure, making them candidates for wave-optical effects if gravitational lensed. If an FRB is lensed into multiple-images bursts at different times by a galaxy or cluster, a likely scenario is that only one image is detected, because the others fall outside the survey area and time frame. Aims: In this work we explore the FRB analog of quasar microlensing, namely the collective microlensing by stars in the lensing galaxy, now with wave optics included. The eikonal regime is applicable here. Methods. We study the voltage (rather than the intensity) in a simple simulation consisting of (a) microlensing stars, and (b) plasma scattering by a turbulent interstellar medium. Results: The auto-correlation of the voltage shows peaks (at order-microsecond separations) corresponding to wave-optical interference between lensed micro-images. The peaks are frequency dependent if plasma-scattering is significant. While qualitative and still in need of more realistic simulations, the results suggest that a strongly-lensed FRB could be identified from a single image. Conclusions: Microlensing could sniff out macro-lensed FRBs
title A possible wave-optical effect in lensed FRBs
topic High Energy Astrophysical Phenomena
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2504.10523