The distribution of FRB fluxes and fluences is characterized by a few very bright events and a deficiency of fainter events compared to expectations for a homogeneous space-filling distribution. I define a metric to quantify this, and apply it to the 17 presently known Parkes FRB, products of a comparatively homogeneous search. With 98\% confidence we reject the hypothesis of a homogeneous distribution in Euclidean space. Possible explanations include a reduction of fainter events by cosmological redshifts or evolution or a cosmologically local concentration of events. The former is opposed by the small value of the one known FRB redshift. The latter contradicts the Cosmological Principle, but may be explained if the brighter FRB originate in the Local Supercluster.
We present constraints on the origins of fast radio bursts (FRBs) using large cosmological simulations. We calculate contributions to FRB dispersion measures (DMs) from the Milky Way, from the local Universe, from cosmological large-scale structure, and from potential FRB host galaxies, and then compare these simulations to the DMs of observed FRBs. We find that the Milky Way contribution has previously been underestimated by a factor of ~2, and that the foreground-subtracted DMs are consistent with a cosmological origin, corresponding to a source population observable to a maximum redshift z~…
Recently, Thornton et al. reported the detection of four fast radio bursts (FRBs). The dispersion measures indicate that the sources of these FRBs are at cosmological distance. Given the large full sky event rate ~ 10^4 sky^-1 day^-1, the FRBs are a promising target for multi-messenger astronomy. Here we propose double degenerate, binary white-dwarf (WD) mergers as the source of FRBs, which are produced by coherent emission from the polar region of a rapidly rotating, magnetized massive WD formed after the merger. The basic characteristics of the FRBs, such as the energetics, emission duration…
Aims: Recently, cosmological fast radio bursts (FRBs) have been used to provide the most stringent limit up to date on Einstein's Equivalence Principle (EEP). We study how to further test EEP with FRBs. Methods: Future systematic radio surveys will certainly find abundant FRBs at cosmological distances and some of them will inevitably be located behind clusters of galaxies. Here we suggest to use those FRBs to further test EEP. Results: We find that the robustness and accuracy of testing EEP can be improved further by orders of magnitude with these FRBs. The same methodology can also be applie…
Nowadays, fast radio bursts (FRBs) have been a promising probe for astronomy and cosmology. However, it is not easy to identify the redshifts of FRBs to date. Thus, no sufficient actual FRBs with identified redshifts can be used to study cosmology currently. In the past years, one has to use the simulated FRBs with "known" redshifts instead. To simulate an FRB, one should randomly assign a redshift to it from a given redshift distribution. But the actual redshift distribution of FRBs is still unknown so far. Therefore, many redshift distributions have been assumed in the literature. In the pre…
Gravitational lensing of fast radio bursts (FRBs) offers an exciting avenue for several cosmological applications. However, it is not yet clear how many such events future surveys will detect nor how to optimally find them. We use the known properties of FRBs to forecast detection rates of gravitational lensing on delay timescales from microseconds to years, corresponding to lens masses spanning fifteen orders of magnitude. We highlight the role of the FRB redshift distribution on our ability to observe gravitational lensing. We consider cosmological lensing of FRBs by stars in foreground gala…
High time resolution radio surveys over the last few years have discovered a population of millisecond-duration transient bursts called Fast Radio Bursts (FRBs), which remain of unknown origin. FRBs exhibit dispersion consistent with propagation through a cold plasma and dispersion measures indicative of an origin at cosmological distances. In this paper we perform Monte Carlo simulations of a cosmological population of FRBs, based on assumptions consistent with observations of their energy distribution, their spatial density as a function of redshift and the properties of the interstellar and…
Modelling DSA, FAST and CRAFT surveys in a z-DM analysis and constraining a minimum FRB energy
International Centre for Radio Astronomy Research, Curtin University（国际射电天文研究中心，科廷大学）；Department of Astronomy and Astrophysics, University of California, Santa Cruz（天文学与天体物理学系，加州大学圣克鲁兹分校）；Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University（天体物理跨学科探索与研究中心（CIERA）及物理与天文学系，西北大学）；Centre for Astrophysics and Supercomputing, Swinburne University of Technology（天体物理学与超级计算中心，斯威本科技大学）；School of Mathematical and Physical Sciences, Macquarie University（数学与物理科学学院，麦考瑞大学）
Fast Radio Burst Cosmology: Hubble Tension and Dark Energy
School of Astronomy and Space Science, Nanjing University（南京大学天文与空间科学学院）；Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education（南京大学现代天文与天体物理教育部重点实验室）；Department of Astronomy, University of Science and Technology of China（中国科学技术大学天文系）
The discovery of a fast radio burst (FRB) in our galaxy associated with a magnetar (neutron star with strong magnetic field) has provided a critical piece of information to help us finally understand these enigmatic transients. We show that the volumetric rate of Galactic-FRB like events is consistent with the faint end of the cosmological FRB rate, and hence they most likely belong to the same class of transients. The Galactic FRB had an accompanying X-ray burst but many X-ray bursts from the same object had no radio counterpart. Their relative rates suggest that for every FRB there are rough…
The role of the galaxy stellar mass function in determining the cosmological distribution of astrophysical transients with applications to fast radio bursts and merging binary black holes
Indian Institute of Astrophysics（印度天体物理研究所）；The Open University of Israel（以色列开放大学）
Fast radio bursts (FRBs) are bright milliseconds radio transients with large dispersion measures. Recently, FRB 200428 was detected in temporal coincidence with a hard X-ray flare from the Galactic magnetar SGR 1935+2154, which supports that at least some FRBs are from magnetar activity. Interestingly, a portion of X-ray flares from magnetar XTE J1810-197 and the Sun are also accompanied by radio bursts. Many features of Galactic FRB 200428 and cosmological FRBs resemble solar radio bursts. However, a common physical origin among FRBs, magnetar radio pulses and solar radio bursts has not yet b…
If a small fraction of Fast Radio Bursts (FRBs) are associated with Gamma-Ray Bursts (GRBs), as recently suggested by Zhang, the combination of redshift measurements of GRBs and dispersion measure (DM) measurements of FRBs opens a new window to study cosmology. At $z<2$ where the universe is essentially fully ionized, detections of FRB/GRB pairs can give an independent measurement of the intergalactic medium portion of the baryon mass fraction, $Ω_b f_{\rm IGM}$, of the universe. If a good sample of FRB/GRB associations are discovered at higher redshifts, the free electron column density histo…
We calculate the dispersion measure (DM) contributed by the intergalactic medium (IGM) to the total measured DM for fast radio bursts (FRBs). We use the MareNostrum Instituto de Ciencias del Espacio (MICE) Onion Universe simulation (Fosalba et al. 2008) to track the evolution of the dark matter particle density over a large range of redshifts. We convert this dark matter particle number density to the corresponding free electron density and then integrate it to find the DM as a function of redshift. This approach yields an intergalactic DM of $\rm DM_{\rm IGM}(z = 1) = 800^{+7000}_{-170}$ pc c…
Fast Radio Bursts (FRBs) are brief radio emissions from distant astronomical sources. Some are known to repeat, but most are single bursts. Non-repeating FRB observations have had insufficient positional accuracy to localize them to an individual host galaxy. We report the interferometric localization of the single pulse FRB 180924 to a position 4 kpc from the center of a luminous galaxy at redshift 0.3214. The burst has not been observed to repeat. The properties of the burst and its host are markedly different from the only other accurately localized FRB source. The integrated electron colum…
There are insufficient catastrophic events (collapse, explosion or merger of stars or compact objects) to explain the cosmologically local rate of apparently non-repeating FRB if each such catastrophic event produces a single FRB. Unless produced by some novel and unsuspected but comparatively frequent event, apparently non-repeating FRB must actually repeat many times in the lifetimes of their sources. Yet no such infrequent repetitions (in contrast to the frequent activity of FRB known to repeat) have been observed, constraining their repetition rates and active lifetimes. The absence of mor…
Fast radio burst (FRB) discoveries are occurring rapidly, with thousands expected from upcoming surveys. The dispersion measures (DM) observed for FRB include important information on cosmological distances and the ionization state of the universe from the redshift of emission until today. Rather than considering the DM--redshift relation, we investigate the statistical ensemble of the distribution of dispersion measures. We explore the use of this abundance information, with and without redshift information, to probe helium reionization. Carrying out Monte Carlo simulations of FRB survey samp…
The widths, dispersion measures, dispersion indices and fluences of Fast Radio Bursts (FRB) impose coupled constraints that all models must satisfy. Observation of dispersion indices close to their low density limit of $-2$ sets a model-independent upper bound on the electron density and a lower bound on the size of any dispersive plasma cloud. The non-monotonic dependence of burst widths (after deconvolution of instrumental effects) on dispersion measure excludes the intergalactic medium as the location of scattering that broadens the FRB in time. Temporal broadening far greater than that of …
Fast radio bursts (FRBs) are millisecond-duration radio signals occurring at cosmological distances. However the physical model of FRBs is mystery, many models have been proposed. Here we study the frequency distributions of peak flux, fluence, duration and waiting time for the repeating FRB 121102. The cumulative distributions of peak flux, fluence and duration show power-law forms. The waiting time distribution also shows power-law distribution, and is consistent with a non-stationary Poisson process. These distributions are similar as those of soft gamma repeaters (SGRs). We also use the st…
Cosmological evolution of fast radio bursts and its rapid decline relative to star formation rate
School of Astronomy and Space Science, Nanjing University（南京大学天文与空间科学学院）；School of Physics and Physical Engineering, Qufu Normal University（曲阜师范大学物理工程学院）；Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, China（教育部现代天文学与天体物理重点实验室（南京大学））
The field of Fast Radio Burst (FRB) science is currently thriving and growing rapidly. The lines of active investigation include theoretical and observational aspects of these enigmatic millisecond radio signals. These pursuits are for the most part intertwined so that each keeps the other in check, characteristic of the healthy state of the field. The immediate future for FRB science is full of promise --- we will in the next few years see two orders of magnitude more FRBs discovered by the now diverse group of instruments spread across the globe involved in these efforts. This increased crop…
Fast radio bursts (FRBs) are radio bursts characterized by millisecond durations, high Galactic latitude positions, and high dispersion measures. Very recently, the cosmological origin of FRB 150418 has been confirmed by \cite{kea16}, and FRBs are now strong competitors as cosmological probes. The simple sharp feature of the FRB signal is ideal for them to probe some of the fundamental laws of physics. Here we show that by analyzing the delay time between different frequencies, the FRB data can place stringent upper limits on the rest mass of the photon. For FRB 150418 at $z=0.492$, one can po…
Recent multi-telescope observations of the repeating Fast Radio Burst FRB 121102 reveal a Gaussian-like spectral profile and associate the event with a dwarf metal-poor galaxy at a cosmological redshift of 0.19. Assuming that this event represents the entire FRB population, we make predictions for the expected number counts of FRBs observable by future radio telescopes between 50 MHz and 3.5 GHz. We vary our model assumptions to bracket the expected rate of FRBs, and find that it exceeds one FRB per second per sky when accounting for faint sources. We show that future low-frequency radio teles…
We examine how the various observable statistical properties of the FRB population relate back to their fundamental physical properties in a model independent manner. We analyse the flux density and fluence distributions of Fast Radio Bursts (FRBs) as a tool to investigate their luminosity distance distribution and the evolution of their prevalence throughout cosmic history. We examine in detail particular scenarios in which the burst population follows some power of the cosmic star formation rate. FRBs present an important additional measurable over source counts of existing cosmological popu…
Fast radio bursts (FRBs) are short duration ($\sim$millisecond) radio transients with cosmological origin. The simple sharp features of the FRB signal have been utilized to probe two fundamental laws of physics, namey, testing Einstein's weak equivalence principle and constraining the rest mass of the photon. Recently, \cite{hessels18} found that after correcting for dispersive delay, some of the bursts in FRB 121102 have complex time-frequency structures that include sub-pulses with a time-frequency downward drifting property. Using the delay time between sub-pulses in FRB 121102, here we sho…
Fast radio bursts (FRBs) are extremely strong radio flares lasting several micro- to milliseconds and come from unidentified objects at cosmological distances, most of which are only seen once. Based on recently published data in the CHIME/FRB Catalog 1 in the frequency bands 400-800 MHz, we analyze 125 apparently singular FRBs with low dispersion measure (DM) and find that the distribution of their luminosity follows a lognormal form according to statistical tests. In our luminosity measurement, the FRB distance is estimated by using the Macquart relation which was obtained for 8 localized FR…
Fast radio bursts (FRBs) are astronomical transients with millisecond timescales occurring at cosmological distances. The observed time lag between different energies of each FRB is well described by the inverse-square law of the observed frequency, i.e., dispersion measure. Therefore, FRBs provide one of the ideal laboratories to test Einstein's weak equivalence principle (WEP): the hypothetical time lag between photons with different energies under a gravitational potential. If WEP is violated, such evidence should be exposed within the observational uncertainties of dispersion measures, unl…
Advanced LIGO and Virgo have reported 90 confident gravitational-wave (GW) observations from compact-binary coalescences from their three observation runs. In addition, numerous subthreshold gravitational-wave candidates have been identified. Binary neutron star (BNS) mergers can produce gravitational waves and short-gamma ray bursts, as confirmed by GW170817/GRB 170817A. There may be electromagnetic counterparts recorded in archival observations associated with subthreshold gravitational-wave candidates. The CHIME/FRB Collaboration has reported the first large sample of fast radio bursts (FRB…
We present Monte-Carlo simulations of a cosmological population of repeating fast radio burst (FRB) sources whose comoving density follows the cosmic star formation rate history. We assume a power-law model for the intrinsic energy distribution for each repeating FRB source located at a randomly chosen position in the sky and simulate their dispersion measures (DMs) and propagation effects along the chosen lines-of-sight to various telescopes. In one scenario, an exponential distribution for the intrinsic wait times between pulses is chosen, and in a second scenario we model the observed pulse…
Fast radio bursts (FRBs) have excessive dispersion measures (DMs) and an all-sky distribution, which point toward an extragalactic or even a cosmological origin. We develop a method to extract the mean host galaxy DM ($\left\langle{\rm DM_{HG,loc}}\right\rangle$) and the characterized luminosity ($L$) of FRBs using the observed DM-Flux data, based on the assumption of a narrow luminosity distribution. Applying Bayesian inference to the data of 21 FRBs, we derive a relatively large mean host DM, i.e. $\left\langle{\rm DM_{HG,loc}}\right\rangle \sim 270~\rm{pc~cm^{-3}}$ with a large dispersion. …
Fast radio bursts (FRB) are millisecond-duration radio pulses with apparent extragalactic origins. All but two of the FRBs have been discovered using the Parkes dish which employs multiple beams formed by an array of feed horns on its focal plane. In this paper, we show that (i) the preponderance of multiple-beam detections, and (ii) the detection rates for varying dish diameters, can be used to infer the index $α$ of the cumulative fluence distribution function (the log$N$-log$F$ function: $α=1.5$ for a non-evolving population in a Euclidean universe). If all detected FRBs arise from a single…
The slope of the source-count distribution of fast radio burst (FRB) fluences, $α$, has been estimated using a variety of methods. Hampering all attempts have been the low number of detected FRBs, and the difficulty of defining a completeness threshold for FRB surveys. In this work, we extend maximum-likelihood methods for estimating $α$, using detected and threshold signal-to-noise ratios applied to all FRBs in a sample without regard to a completeness threshold. Using this method with FRBs detected by the Parkes radio telescope, we find $α=-1.18 \pm 0.24$ (68\% confidence interval, C.I.), i.…
The recent discovery of a Galactic fast radio burst (FRB) associated with a hard X-ray burst from the soft gamma-ray repeater (SGR) J1935+2154 has established the magnetar origin of at least some FRBs. In this work, we study the statistical properties of soft gamma-/hard X-ray bursts from SGRs 1806--20 and J1935+2154 and of radio bursts from the repeating FRB 121102. For SGRs, we show that the probability density functions for the differences of fluences, fluxes, and durations at different times have fat tails with a $q$-Gaussian form. The $q$ values in the $q$-Gaussian distributions are appro…
Updating the PATH framework with FRB host galaxy models
Curtin University（科廷大学）；Kavli Institute for the Physics and Mathematics of the Universe（宇宙物理与数学卡弗里研究所）；National Astronomical Observatory of Japan（日本国立天文台）；Macquarie University（麦考瑞大学）；CSIRO Space & Astronomy（CSIRO空间与天文部）；Princeton University（普林斯顿大学）；University of California, Santa Cruz（加州大学圣克鲁兹分校）
