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Register a new userA Living Theory Catalogue for Fast Radio Bursts
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At present, we have almost as many theories to explain Fast Radio Bursts as we have Fast Radio Bursts observed. This landscape will be changing rapidly with CHIME/FRB, recently commissioned in Canada, and HIRAX, under construction in South Africa. This is an opportune time to review existing theories and their observational consequences, allowing us to efficiently curtail viable astrophysical models as more data becomes available. In this article we provide a currently up to date catalogue of the numerous and varied theories proposed for Fast Radio Bursts so far. We also launch an online evolving repository for the use and benefit of the community to dynamically update our theoretical knowledge and discuss constraints and uses of Fast Radio Bursts.
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Fast Radio Bursts (FRBs), characterized by strong bursts of radiation intensity at radio wavelengths lasting on the order of a millisecond, have yet to be firmly associated with a family, or families, of astronomical sources. It follows that despite the large number of proposed models no well-defined physical process has been identified to explain this phenomenon. In this paper, we demonstrate how Dickes superradiance, for which evidence has recently been found in the interstellar medium, can account for the characteristics associated to FRBs. Our analysis and modelling of previously detected FRBs suggest they could originate from regions in many ways similar to those known to harbor masers or megamasers, and result from the coherent radiation emanating from populations of molecules associated with large-scale entangled quantum mechanical states. We estimate this entanglement to involve as many as ~10^(30) to ~10^(32) molecules over distances spanning 100 to 1000 AU.
The detection of six Fast Radio Bursts (FRBs) has recently been reported. FRBs are short duration ($sim$ 1 ms), highly dispersed radio pulses from astronomical sources. The physical interpretation for the FRBs remains unclear but is thought to involve highly compact objects at cosmological distance. It has been suggested that a fraction of FRBs could be physically associated with gamma-ray bursts (GRBs). Recent radio observations of GRBs have reported the detection of two highly dispersed short duration radio pulses using a 12 m radio telescope at 1.4 GHz. Motivated by this result, we have performed a systematic and sensitive search for FRBs associated with GRBs. We have observed five GRBs at 2.3 GHz using a 26 m radio telescope located at the Mount Pleasant Radio Observatory, Hobart. The radio telescope was automated to rapidly respond to Gamma-ray Coordination Network notifications from the Swift satellite and slew to the GRB position within $sim$ 140 s. The data were searched for pulses up to 5000 pc $rm cm^{-3}$ in dispersion measure and pulse widths ranging from 640 $rm mu$s to 25.60 ms. We did not detect any events $rm geq 6 sigma$. An in-depth statistical analysis of our data shows that events detected above $rm 5 sigma$ are consistent with thermal noise fluctuations only. A joint analysis of our data with previous experiments shows that previously claimed detections of FRBs from GRBs are unlikely to be astrophysical. Our results are in line with the lack of consistency noted between the recently presented FRB event rates and GRB event rates.
In this paper we identify some sub-optimal performance in algorithms that search for Fast Radio Bursts (FRBs), which can reduce the cosmological volume probed by over 20%, and result in missed discoveries and incorrect flux density and sky rate determinations. Re-calculating parameters for all of the FRBs discovered with the Parkes telescope (i.e. all of the reported FRBs bar one), we find some inconsistencies with previously determined values, e.g. FRB 010125 was approximately twice as bright as previously reported. We describe some incompleteness factors not previously considered which are important in determining accurate population statistics, e.g. accounting for fluence incompleteness the Thornton et al. all-sky rate can be re-phrased as ~2500 FRBs per sky per day above a 1.4-GHz fluence of ~2 Jy ms. Finally we make data for the FRBs easily available, along with software to analyse these.
Since their serendipitous discovery, Fast Radio Bursts (FRBs) have garnered a great deal of attention from both observers and theorists. A new class of radio telescopes with wide fields of view have enabled a rapid accumulation of FRB observations, confirming that FRBs originate from cosmological distances. The high occurrence rate of FRBs and the development of new instruments to observe them create opportunities for FRBs to be utilized for a host of astrophysical and cosmological studies. We focus on the rare, and as yet undetected, subset of FRBs that undergo repeated bursts and are strongly gravitationally lensed by intervening structure. An extremely precise timing of burst arrival times is possible for strongly lensed repeating FRBs, and we show how this timing precision enables the search for long wavelength gravitational waves, including those sourced by supermassive black hole binary systems. The timing of burst arrival for strongly lensed repeating FRBs is sensitive to gravitational wave sources near the FRB host galaxy, which may lie at cosmological distances and would therefore be extremely challenging to detect by other means. Timing of strongly lensed FRBs can also be combined with pulsar timing array data to search for correlated time delays characteristic of gravitational waves passing through the Earth.
We have searched three Parkes multibeam 1.4 GHz surveys for the presence of fast radio bursts (FRBs) out to a dispersion measure (DM) of 5000 pc cm$^{-3}$. These surveys originally targeted the Magellanic Clouds (in two cases) and unidentified gamma-ray sources at mid-Galactic latitudes (in the third case) for new radio pulsars. In previous processing, none of these surveys were searched to such a high DM limit. The surveys had a combined total of 719 hr of Parkes multibeam on-sky time. One known FRB, 010724, was present in our data and was detected in our analysis but no new FRBs were found. After adding in the on-sky Parkes time from these three surveys to the on-sky time (7512 hr) from the five Parkes surveys analysed by Rane et al., all of which have now been searched to high DM limits, we improve the constraint on the all-sky rate of FRBs above a fluence level of 3.8 Jy ms at 1.4 GHz to $R = 3.3^{+3.7}_{-2.2} times 10^{3}$ events per day per sky (at the 99% confidence level). Future Parkes surveys that accumulate additional multibeam on-sky time (such as the ongoing high-resolution Parkes survey of the LMC) can be combined with these results to further constrain the all-sky FRB rate.
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