FRBs Lensed by Point Masses II. The multi-peaked FRBs from the point view of microlensing

Abstract

The microlensing effect has developed into a powerful technique for a diverse range of applications including exoplanet discoveries, structure of the Milky Way, constraints on MAssive Compact Halo Objects, and measurements of the size and profile of quasar accretion discs. In this paper, we consider a special type of microlensing events where the sources are fast radio bursts with $\sim$milliseconds (ms) durations for which the relative motion between the lens and source is negligible. In this scenario, it is possible to temporally resolve the individual microimages. As a result, a method beyond the inverse ray shooting (IRS) method, which only evaluates the total magnification of all microimages, is needed. We therefore implement an algorithm for identifying individual microimages and computing their magnifications and relative time delays. We validate our algorithm by comparing to analytical predictions for a single microlens case and find excellent agreement. We show that the superposition of pulses from individual microimages produces a light curve that appears as multi-peaked FRBs. The relative time delays between pulses can reach 0.1--1 ms for stellar-mass lenses and hence can already be resolved temporally by current facilities. Although not yet discovered, microlensing of FRBs will become regular events and surpass the number of quasar microlensing events in the near future when $10^{4-5}$ FRBs are expected to be discovered on a daily basis. Our algorithm provides a way of generating the microlensing light curve that can be used for constraining stellar mass distribution in distant galaxies.

14 pages, 6 figures, accepted for publication in ApJ

References in corpus (16)

• A bright millisecond radio burst of extragalactic origin
• The direct localization of a fast radio burst and its host
• The Host Galaxy and Redshift of the Repeating Fast Radio Burst FRB 121102
• Fast Radio Bursts
• A repeating fast radio burst source localised to a nearby spiral galaxy
• A Second Source of Repeating Fast Radio Bursts
• Nine New Repeating Fast Radio Burst Sources from CHIME/FRB
• Understanding caustic crossings in giant arcs: characteristic scales, event rates, and constraints on compact dark matter
• The Physics of Fast Radio Bursts
• X-Ray and Optical Microlensing in the Lensed Quasar PG 1115+080
• Limits on the Mass and Abundance of Primordial Black Holes from Quasar Gravitational Microlensing
• Fast radio bursts to be detected with the Square Kilometre Array
• Probing motion of fast radio burst sources by timing strongly lensed repeaters
• Size of the accretion disk in the gravitationally lensed quasar SDSS J1004+4112 from the statistics of microlensing magnifications
• FRBs Lensed by Point Masses I. Lens Mass Estimation for Doubly Imaged FRBs
• Gravitational Microlensing Time Delays at High Optical Depth: Image Parities and the Temporal Properties of Fast Radio Bursts

Cited by in corpus (7)

• FAST observations of an extremely active episode of FRB 20201124A: IV. Spin Period Search
• Stellar prospects for FRB gravitational lensing
• The effects of plasma on the magnification and time delay of strongly lensed fast radio bursts
• Wave effect of gravitational waves intersected with a microlens field: a new algorithm and supplementary study
• Microlensing bias on the detection of strong lensing gravitational wave
• Wave effect of gravitational waves intersected with a microlens field II: an adaptive hierarchical tree algorithm and population study
• An interference-based method for the detection of strongly lensed gravitational waves