An analysis of the time-frequency structure of several bursts from FRB 121102 detected with MeerKAT

Platts, Emma; Caleb, M.; Stappers, B. W.; Main, Robert; Weltman, Amanda; Shock, Jonathan P.; Krämer, M.; Bezuidenhout, Mechiel Christiaan; Jankowski, F.; Morello, Vincent; Possenti, A.; Rajwade, Kaustubh; Rhodes, L.; Wu, J.

doi:10.1093/mnras/stab1544

Cited by 29 publications

(34 citation statements)

References 62 publications

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“…This repeating nature allowed for follow-up observations that localised the source to near a star-forming region in a dwarf galaxy at redshift 𝑧 = 0.193 (Bassa et al 2017;Chatterjee et al 2017;Tendulkar et al 2017) and, moreover, a milliarcsecond association of the bursts with a persistent compact radio source (Marcote et al 2017). The most recent dispersion measure (DM) measurements of the bursts from FRB 20121102A are 563.5±0.8 pc cm −3 on MJD 57836 (Platts et al 2021) and 565.8 ± 0.8 pc cm −3 for the period between MJD 58724 and MJD 58776 (Li et al 2021). Li et al (2021) also estimated that this DM is increasing by approximately 1 pc cm −3 yr −1 .…”

Section: Introductionmentioning

confidence: 99%

Arecibo observations of a burst storm from FRB 20121102A in 2016

Hewitt¹,

Snelders²,

Hessels³

et al. 2021

Preprint

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FRB 20121102A is the first known fast radio burst (FRB) from which repeat bursts were detected, and one of the best-studied FRB sources in the literature. Here we report on the analysis of 478 bursts from FRB 20121102A using the 305-m Arecibo telescope, detected during approximately 59 hours of observations between December 2015 and October 2016. The majority of bursts are from a burst storm around September 2016. This is the earliest available sample of a large number of FRB 20121102A bursts, and it thus provides an anchor point for long-term studies of the source's evolving properties. We observe that the bursts separate into two groups in the width-bandwidth-energy parameter space, which we refer to as the low-energy bursts (LEBs) and high-energy bursts (HEBs). We find that the LEBs are typically longer duration and narrower bandwidth than the HEBs. This is reminiscent of the spectro-temporal differences observed between the bursts of repeating and non-repeating FRBs. We fit the cumulative burst rate-energy distribution with a broken power-law and find that it flattens out toward higher energies. The bursts in this sample comprise a diverse zoo of burst morphologies, but notably burst emission seems to be more common at the top than the bottom of our observing frequency range (∼ 1150 − 1730 MHz). We also observe that bursts from the same day appear to be more similar to each other than to those of other days, but this observation requires confirmation. The wait times and burst rates that we measure are consistent with previous studies.

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Section: Introductionmentioning

confidence: 99%

Arecibo observations of a burst storm from FRB 20121102A in 2016

Hewitt¹,

Snelders²,

Hessels³

et al. 2021

Preprint

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“…One of the fundamental properties of emission from the FRB sources is the dispersion, with its strength parametrized by the dispersion measure (DM), a measure of the electron column density along the line of sight. The difficulty in making an accurate determination of an FRB DM is compounded by the spectro-temporal evolution seen in the burst emission (Platts et al 2021), which can be degenerate with DM and lead to ambiguities (Hassall et al 2012). Here we outline how we measured the DM of these repeat bursts.…”

Section: Dispersion Measurementioning

confidence: 99%

“…We fitted the obtained S/N-DM curve (Cordes & McLaughlin 2003) with a higher degree (10) polynomial and used the peak to establish the DM for each burst. The uncertainty in DM is calculated by propagating the uncertainty given by the residuals of the polynomial fitting (Platts et al 2021). We report the measured DM with uncertainties for all repeat bursts in Table 1.…”

Section: Dispersion Measurementioning

confidence: 99%

“…The dynamic burst structures of FRBs depend on the accurate determination of DM and could easily result in over-interpretation (Platts et al 2021). Our earlier analysis of the Parkes repeat burst P05 is based on DM = 413 pc cm −3 which we obtain from the statistical average of a sample of bright bursts.…”

Section: Burst P05 Sub-structurementioning

confidence: 99%

“…Bursts from repeating FRB sources tend to have their dynamic spectrum drifting downwards in frequency (Hessels et al 2019). It is not clear if this drifting along with multiple components embedded into each other (Platts et al 2021) which results in "extra dispersion" in the burst structure, is propagation-induced or caused due to intrinsic mechanisms in the progenitor. The dilemma in deciding the best-DM or the correct alignment of the burst structure creates difficulty in studying the spectrum and its dependence on the observed frequency.…”

Section: Burst P05 Sub-structurementioning

confidence: 99%

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Circularly polarized radio emission from the repeating fast radio burst source FRB 20201124A

Kumar,

Shannon,

Lower

et al. 2021

Preprint

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The mechanism that produces fast radio burst (FRB) emission is poorly understood. Targeted monitoring of repeating FRB sources provides the opportunity to fully characterise the emission properties in a manner impossible with one-off bursts. Here we report observations of the source of FRB 20201124A, with the Australian Square Kilometre Array Pathfinder (ASKAP) and the Ultra-wideband Low (UWL) receiver at the Parkes 64-m radio telescope (Murriyang). The source entered a period of emitting bright bursts during early April 2021. We have detected 16 bursts from this source. One of the bursts detected with ASKAP is the brightest burst ever observed from a repeating FRB source with an inferred fluence of 640 ± 70 Jy ms. Of the five bursts detected with the UWL, none display any emission in the range 1.1-4 GHz. All UWL bursts are highly polarized, and we obtain an average Faraday rotation measure of −613 ± 2 rad m −2 for this source. In one of the UWL bursts, we see evidence of significant circularly-polarized emission with a fractional extent of 47%. Such a high degree of circular polarisation has never been seen before in bursts from repeating FRB sources. We also see evidence for variation in the polarization position angle in this UWL burst. Models for repeat burst emission will need to account for increasing diversity in the burst polarization properties.

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A fast radio burst source at a complex magnetized site in a barred galaxy

Niu

Chen

et al. 2022

Nature

127

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Fast radio bursts (FRBs) are highly dispersed radio bursts prevailing in the universe [1][2][3] . The recent detection of FRB 200428 from a Galactic magnetar [4][5][6][7][8] suggested that at least some FRBs originate from magnetars, but it is unclear whether the majority of cosmological FRBs, especially the actively repeating ones, are produced from the magnetar channel. Here we report the detection of 1863 polarised bursts from the repeating source FRB 20201124A 9 during a dedicated radio observational campaign of Five-hundred-meter Aperture Spherical radio Telescope (FAST). The large sample of radio bursts detected in 88 hr over 54 days indicate a significant, irregular, short-time variation of the Faraday rotation measure (RM) of the source during the first 36 days, followed by a constant RM during the later 18 days. Significant circular polarisation up to 75% was observed in a good fraction of bursts. Evidence suggests that some low-level circular polarisation originates from the conversion from linear polarisation during the propagation of the radio waves, but an intrinsic radiation mechanism is required to produce the higher degree of circular polarisation. All of these features provide evidence for a more complicated, dynamically evolving, magnetised immediate environment around this FRB source. Its host galaxy was previously known 10-12 . Our optical observations reveal that it is a Milky-Way-sized, metal-rich, barred-spiral galaxy at redshift z = 0.09795 ± 0.00003, with the FRB source residing in a low stellar density, interarm region

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An analysis of the time-frequency structure of several bursts from FRB 121102 detected with MeerKAT

Cited by 29 publications

References 62 publications

Arecibo observations of a burst storm from FRB 20121102A in 2016

Arecibo observations of a burst storm from FRB 20121102A in 2016

Circularly polarized radio emission from the repeating fast radio burst source FRB 20201124A

A fast radio burst source at a complex magnetized site in a barred galaxy

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