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Scattering variability detected from the circumsource medium of FRB 20190520B

Ocker, Stella Koch and Cordes, James M. and Chatterjee, Shami and Li, Di and Niu, Chen-Hui and McKee, James W. and Law, Casey J. and Anna-Thomas, Reshma (2023) Scattering variability detected from the circumsource medium of FRB 20190520B. Monthly Notices of the Royal Astronomical Society, 519 (1). pp. 821-830. ISSN 0035-8711. doi:10.1093/mnras/stac3547.

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Fast radio bursts (FRBs) are millisecond-time-scale radio transients, the origins of which are predominantly extragalactic and likely involve highly magnetized compact objects. FRBs undergo multipath propagation, or scattering, from electron density fluctuations on sub-parsec scales in ionized gas along the line of sight. Scattering observations have located plasma structures within FRB host galaxies, probed Galactic and extragalactic turbulence, and constrained FRB redshifts. Scattering also inhibits FRB detection and biases the observed FRB population. We report the detection of scattering times from the repeating FRB 20190520B that vary by up to a factor of 2 or more on minutes to days-long time-scales. In one notable case, the scattering time varied from 7.9 ± 0.4 ms to less than 3.1 ms (⁠95 per cent confidence) over 2.9 min at 1.45 GHz. The scattering times appear to be uncorrelated between bursts or with dispersion and rotation measure variations. Scattering variations are attributable to dynamic, inhomogeneous plasma in the circumsource medium, and analogous variations have been observed from the Crab pulsar. Under such circumstances, the frequency dependence of scattering can deviate from the typical power law used to measure scattering. Similar variations may therefore be detectable from other FRBs, even those with inconspicuous scattering, providing a unique probe of small-scale processes within FRB environments.

Item Type:Article
Related URLs:
URLURL TypeDescription
Ocker, Stella Koch0000-0002-4941-5333
Cordes, James M.0000-0002-4049-1882
Chatterjee, Shami0000-0002-2878-1502
Li, Di0000-0003-3010-7661
Niu, Chen-Hui0000-0001-6651-7799
McKee, James W.0000-0002-2885-8485
Law, Casey J.0000-0002-4119-9963
Anna-Thomas, Reshma0000-0001-8057-0633
Additional Information:The authors thank the anonymous referee, Paz Beniamini, and Jason Hessels for their comments on this work. SKO, JMC, and SC acknowledge support from the National Science Foundation (AAG-1815242) and are members of the NANOGrav Physics Frontiers Center, which is supported by NSF award PHY-2020265. CHN is supported by the FAST Fellowship and DL acknowledges support from the National Natural Science Foundation of China (NSFC) Programs No. 11988101 and No. 11725313. JWM gratefully acknowledges support by the Natural Sciences and Engineering Research Council of Canada (NSERC) (funding reference #CITA 490888-16). CJL acknowledges support from the National Science Foundation under Grant No. 2022546. RAT acknowledges support from NSF grant AAG-1714897.
Funding AgencyGrant Number
Michigan State UniversityUNSPECIFIED
National Natural Science Foundation of China11988101
National Natural Science Foundation of China11725313
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Issue or Number:1
Record Number:CaltechAUTHORS:20230213-466109600.22
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ID Code:119247
Deposited By: Research Services Depository
Deposited On:24 Mar 2023 00:03
Last Modified:24 Mar 2023 00:03

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