Probing motion of fast radio burst sources by timing strongly lensed repeaters

Abstract

Given the possible repetitive nature of fast radio bursts (FRBs), their cosmological origin, and their high occurrence, detection of strongly lensed sources due to intervening galaxy lenses is possible with forthcoming radio surveys. We show that if multiple images of a repeating source are resolved with VLBI, using a method independent of lens modeling, accurate timing could reveal non-uniform motion, either physical or apparent, of the emission spot. This can probe the physical nature of FRBs and their surrounding environments, constraining scenarios including orbital motion around a stellar companion if FRBs require a compact star in a special system, and jet-medium interactions for which the location of the emission spot may randomly vary. The high timing precision possible for FRBs ($\sim \mathrm{ms}$) compared to the typical time delays between images in galaxy lensing ($\gtrsim 10\mathrm{days}$) enables the measurement of tiny fractional changes in the delays ($\sim 10^{-9}$), and hence the detection of time-delay variations induced by relative motions between the source, the lens, and the Earth. We show that uniform cosmic peculiar velocities only cause the delay time to drift linearly, and that the effect from the Earth's orbital motion can be accurately subtracted, thus enabling a search for non-trivial source motion. For a timing accuracy of $\sim 1$ms and a repetition rate (of detected bursts) $\sim 0.05$ per day of a single FRB source, non-uniform displacement $\gtrsim 0.1-1$AU of the emission spot perpendicular to the line of sight is detectable if repetitions are seen over a period of hundreds of days.

21 pages, 6 figures, 1 table. New version accepted to ApJ with abstract revised, typo corrected, and references added

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Cited by in corpus (22)

• The Physics of Fast Radio Bursts
• The Physics of Fast Radio Bursts
• Cosmology-independent estimate of the fraction of baryon mass in the IGM from fast radio burst observations
• Cosmology-insensitive estimate of IGM baryon mass fraction from five localized fast radio bursts
• Cosmology with gravitationally lensed repeating Fast Radio Bursts
• Modelling the water and carbon dioxide production rates of Comet 67P/Churyumov-Gerasimenko
• Search for lensing signatures from the latest fast radio burst observations and constraints on the abundance of primordial black holes
• Prospects of strongly lensed repeating fast radio bursts: complementary constraints on dark energy evolution
• The effects of plasma lensing on the inferred dispersion measures of Fast Radio Bursts
• A High-Time Resolution Search for Compact Objects using Fast Radio Burst Gravitational Lens Interferometry with CHIME/FRB
• The effects of plasma on the magnification and time delay of strongly lensed fast radio bursts
• Detecting Dark Matter Substructures on Small Scales with Fast Radio Bursts
• Searching for Gravitational Waves with Strongly Lensed Repeating Fast Radio Bursts
• Detecting Cosmic Strings with Lensed Fast Radio Bursts
• Finding the Particularity of the Active Episode of SGR J1935+2154 during Which FRB 20200428 Occurred: Implication from Statistics of Fermi/GBM X-Ray Bursts
• FRBs Lensed by Point Masses II. The multi-peaked FRBs from the point view of microlensing
• Probing Gravitational Slip with Strongly Lensed Fast Radio Bursts
• Associating fast radio bursts with compact binary mergers via gravitational lensing
• Hunting Galactic Axion Dark Matter with Gravitationally Lensed Fast Radio Bursts
• Combining strongly lensed and unlensed fast radio bursts: To be a more precise late-universe probe
• Scintillometry of Fast Radio Bursts: Resolution effects in two-screen models
• Lensing cosmic drift