Lensing of Fast Radio Bursts by Plasma Structures in Host Galaxies

By J. Cordes, I. Wasserman, Jason W. T. Hessels, T. Lazio, S. Chatterjee, R. Wharton. 2017

141 citations recorded by the source corpus.

The amplitudes of fast radio bursts (FRBs) can be strongly modulated by plasma lenses in their host galaxies, including that of the repeating FRB 121102 at ∼1 Gpc luminosity distance. Caustics require the lens’ dispersion measure depth ( ), scale size (a), and distance from the source ( ) to satisfy . Caustics produce strong magnifications ( ) on short timescales ( hours to days) that appear as narrow spectral peaks (0.1–1 GHz). They also suppress the flux density in longer-duration (∼months) troughs. Multiply imaged bursts will arrive differentially by to tens of ms with different apparent dispersion measures, pc cm−3. When differing by less than the burst width, interference effects in dynamic spectra will be seen. Larger arrival time perturbations may mask any underlying periodicity with period . Strong lensing requires sources smaller than , which includes compact objects such as neutron star magnetospheres but excludes active galactic nuclei. We discuss constraints on densities, magnetic fields, and locations of plasma lenses related to the conditions needed for lensing to occur. Much of the phenomenology of the repeating FRB source FRB 121102 can be accounted for in this picture, which can be tested by obtaining wideband spectra of bursts (from to 10 GHz and possibly higher) that will also help characterize the plasma environment near FRB sources. A rich variety of phenomena is expected from an ensemble of lenses near an FRB source.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/9637525f8ff2f6d6848787b73df793423aa42083

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Citations in the corpus

A Multi-telescope Campaign on FRB 121102: Implications for the FRB Population (2017, background): “Radio bursts from FRB 121102 require either dramatic scaling of known emission processes (Lyutikov et al. 2016; Cordes & Wasserman 2016) and/or strong amplification by propagation effects (Cordes et al. 2017).”
A living theory catalogue for fast radio bursts (2018, background): “e range in repetition rates (Caleb et al., 2019). Further, the observed repetition or lack thereof can be strongly aﬀected by interstellar scintillations (Cordes and Rickett, 1998) or plasma lensing (Cordes et al., 2017; Main et al., 2018; Spitler et al., 2018). FRB 121102 was found to have a rotati”
Fast radio bursts at the dawn of the 2020s (2021, unknown): “This can both inform progenitor models as well as whether the observed burst properties are predominantly intrinsic, or mainly reflect local propagation effects, like plasma lensing (Cordes et al. 2017).”
Fast radio bursts as synchrotron maser emission from decelerating relativistic blast waves (2019, background): “Temporalfrequency evolution could be imprinted by plasma lensing effects during the propagation to Earth (e.g. Cordes et al. 2017; Main et al. 2018) rather than being an intrinsic property of the bursts.”
Fast Radio Burst Morphology in the First CHIME/FRB Catalog (2021, background): “Cordes et al. (2017) proposed plasma lensing as a way to explain the complex time/frequency patterns, which we now recognize as typical of the repeating FRB population, in the first discovered repeater, FRB 20121102A (e.g., Hessels et al. 2019).”