The Spectral Properties of the Bright Fast Radio Burst Population
We examine the spectra of 23 fast radio bursts (FRBs) detected in a fly's-eye survey with the Australian SKA Pathfinder, including those of three bursts not previously reported. The mean spectral index of α = -1.5 -0.3+0.2 (Fv ∞ v α) is close to that of the Galactic pulsar population. The sampl...
| Main Authors: | , , , , , |
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| Format: | Journal Article |
| Published: |
2019
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/1810.04353 http://hdl.handle.net/20.500.11937/91555 |
| _version_ | 1848765546410016768 |
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| author | Macquart, Jean-Pierre Shannon, Ryan Bannister, K.W. James, Clancy Ekers, Ronald Bunton, J.D. |
| author_facet | Macquart, Jean-Pierre Shannon, Ryan Bannister, K.W. James, Clancy Ekers, Ronald Bunton, J.D. |
| author_sort | Macquart, Jean-Pierre |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We examine the spectra of 23 fast radio bursts (FRBs) detected in a fly's-eye survey with the Australian SKA Pathfinder, including those of three bursts not previously reported. The mean spectral index of α = -1.5 -0.3+0.2 (Fv ∞ v α) is close to that of the Galactic pulsar population. The sample is dominated by bursts exhibiting a large degree of spectral modulation: 17 exhibit fine-scale spectral modulation with an rms exceeding 50% of the mean, with decorrelation bandwidths (half-maximum) ranging from ≈1 to 49 MHz. Most decorrelation bandwidths are an order of magnitude lower than the ≳30 MHz expected of Galactic interstellar scintillation at the Galactic latitude of the survey, |b| = 50° ± 5°. However, these bandwidths are consistent with the ∼v 4 scaling expected of diffractive scintillation when compared against the spectral structure observed in bright UTMOST FRBs detected at 843 MHz. A test of the amplitude distribution of the spectral fluctuations reveals only 12 bursts consistent at better than a 5% confidence level with the prediction of 100%-modulated diffractive scintillation. Five of six FRBs with a signal-tonoise ratio exceeding 20 are only consistent with this prediction at less than 1% confidence. Nonetheless, there is weak evidence (92%-94% confidence) of an anti-correlation between the amplitude of the spectral modulation and dispersion measure (DM), which suggests that it originates as a propagation effect. This effect is corroborated by the smoothness of the higher-DM Parkes FRBs, and could arise due to quenching of diffractive scintillation (e.g., in the interstellar medium of the host galaxy) by angular broadening in the intergalactic medium. |
| first_indexed | 2025-11-14T11:36:58Z |
| format | Journal Article |
| id | curtin-20.500.11937-91555 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T11:36:58Z |
| publishDate | 2019 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-915552023-05-11T04:37:42Z The Spectral Properties of the Bright Fast Radio Burst Population Macquart, Jean-Pierre Shannon, Ryan Bannister, K.W. James, Clancy Ekers, Ronald Bunton, J.D. astro-ph.HE astro-ph.HE We examine the spectra of 23 fast radio bursts (FRBs) detected in a fly's-eye survey with the Australian SKA Pathfinder, including those of three bursts not previously reported. The mean spectral index of α = -1.5 -0.3+0.2 (Fv ∞ v α) is close to that of the Galactic pulsar population. The sample is dominated by bursts exhibiting a large degree of spectral modulation: 17 exhibit fine-scale spectral modulation with an rms exceeding 50% of the mean, with decorrelation bandwidths (half-maximum) ranging from ≈1 to 49 MHz. Most decorrelation bandwidths are an order of magnitude lower than the ≳30 MHz expected of Galactic interstellar scintillation at the Galactic latitude of the survey, |b| = 50° ± 5°. However, these bandwidths are consistent with the ∼v 4 scaling expected of diffractive scintillation when compared against the spectral structure observed in bright UTMOST FRBs detected at 843 MHz. A test of the amplitude distribution of the spectral fluctuations reveals only 12 bursts consistent at better than a 5% confidence level with the prediction of 100%-modulated diffractive scintillation. Five of six FRBs with a signal-tonoise ratio exceeding 20 are only consistent with this prediction at less than 1% confidence. Nonetheless, there is weak evidence (92%-94% confidence) of an anti-correlation between the amplitude of the spectral modulation and dispersion measure (DM), which suggests that it originates as a propagation effect. This effect is corroborated by the smoothness of the higher-DM Parkes FRBs, and could arise due to quenching of diffractive scintillation (e.g., in the interstellar medium of the host galaxy) by angular broadening in the intergalactic medium. 2019 Journal Article http://hdl.handle.net/20.500.11937/91555 10.3847/2041-8213/ab03d6 https://arxiv.org/abs/1810.04353 http://purl.org/au-research/grants/arc/DP180100857 http://purl.org/au-research/grants/arc/FL150100148 http://purl.org/au-research/grants/arc/CE17010000 restricted |
| spellingShingle | astro-ph.HE astro-ph.HE Macquart, Jean-Pierre Shannon, Ryan Bannister, K.W. James, Clancy Ekers, Ronald Bunton, J.D. The Spectral Properties of the Bright Fast Radio Burst Population |
| title | The Spectral Properties of the Bright Fast Radio Burst Population |
| title_full | The Spectral Properties of the Bright Fast Radio Burst Population |
| title_fullStr | The Spectral Properties of the Bright Fast Radio Burst Population |
| title_full_unstemmed | The Spectral Properties of the Bright Fast Radio Burst Population |
| title_short | The Spectral Properties of the Bright Fast Radio Burst Population |
| title_sort | spectral properties of the bright fast radio burst population |
| topic | astro-ph.HE astro-ph.HE |
| url | https://arxiv.org/abs/1810.04353 https://arxiv.org/abs/1810.04353 https://arxiv.org/abs/1810.04353 https://arxiv.org/abs/1810.04353 http://hdl.handle.net/20.500.11937/91555 |