Implications of Canadian Hydrogen Intensity Mapping Experiment repeating fast radio bursts
- Creators
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Lu, Wenbin
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Piro, Anthony L.
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Waxman, Eli
Abstract
CHIME has now detected 18 repeating fast radio bursts (FRBs). We explore what can be learned about the energy distribution and activity level of the repeaters by fitting realistic FRB population models to the data. For a power-law energy distribution dN/dE ∝ E^(−γ) for the repeating bursts, there is a critical index γcrit that controls whether the dispersion measure (DM, a proxy for source distance) distribution of repeaters is bottom or top-heavy. We find γ_(crit) = 7/4 for Poisson wait-time distribution of repeaters in Euclidean space and further demonstrate how it is affected by temporal clustering of repetitions and cosmological effects. It is especially interesting that two of the CHIME repeaters (FRB 181017 and 190417) have large DM∼10³pc cm⁻³. These can be understood if: (i) the energy distribution is shallow γ = 1.7^(+0.3)_(−0.1) 68 per cent confidence) or (ii) a small fraction of sources are extremely active. In the second scenario, these two high-DM sources should be repeating more than 100 times more frequently than FRB 121102 and the energy index is constrained to be γ = 1.9^(+0.3)_(−0.2) (68 per cent confidence). In either case, this γ is consistent with the energy dependence of the non-repeating ASKAP sample, which suggests that they are drawn from the same population. Finally, our model predicts how the CHIME repeating fraction should decrease with redshift and this can be compared with observations to infer the distribution of activity level in the whole population.
Additional Information
© 2020 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). Accepted 2020 July 27. Received 2020 July 10; in original form 2020 March 24. Published: 31 August 2020. We thank Paz Beniamini for useful discussions. We thank the organizers for the 2019 Toronto FRB Day workshop and the 2020 Flatiron Institute FRB workshop, where the current work was initiated. WL is supported by the David and Ellen Lee Fellowship at Caltech. Data Availability: The data underlying this article will be shared on reasonable request to the corresponding author.Attached Files
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Additional details
- Eprint ID
- 107057
- Resolver ID
- CaltechAUTHORS:20201214-085718623
- David and Lucile Packard Foundation
- David and Ellen Lee Postdoctoral Scholarship
- Created
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2020-12-14Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field
- Caltech groups
- TAPIR, Walter Burke Institute for Theoretical Physics