Sample Of Fast Radio Bursts Research Articles

On the Energy Budget of Starquake-induced Repeating Fast Radio Bursts

With a growing sample of fast radio bursts (FRBs), we investigate the energy budget of different power sources within the framework of magnetar starquake triggering mechanism. During a starquake, the energy can be released in any form through strain, magnetic, rotational, and gravitational energies. The strain energy can be converted from three other kinds of energy during starquakes. The following findings are revealed: (1) The crust can store free magnetic energy of ∼1046 erg by existing toroidal fields, sustaining 106 bursts with frequent starquakes occurring due to crustal instability. (2) The strain energy develops as a rigid object spins down, which can be released during a global starquake accompanied by a glitch. However, it takes a long time to accumulate enough strain energy via spindown. (3) The rotational energy of a magnetar with P ≲ 0.1 s can match the energy and luminosity budget of FRBs. (4) The budget of the total gravitational energy is high, but the mechanism and efficiency of converting this energy to radiation deserve further exploration.

The Origins of Narrow Spectra of Fast Radio Bursts

Observations find that some fast radio bursts (FRBs) have extremely narrowband spectra, i.e., Δν/ν 0 ≪ 1. We show that, when the angular size of the emission region is larger than the Doppler beaming angle, the observed spectral width (Δν/ν 0) exceeds 0.58 due to the high-latitude effects for a source outside the magnetosphere, even when the spectrum in the source’s comoving frame is monochromatic. The angular size of the source for magnetospheric models of FRBs can be smaller than the Doppler beaming angle, in which case this geometric effect does not influence the observed bandwidth. We discuss various propagation effects to determine if any could transform a broad-spectrum radio pulse into a narrow spectrum signal at the observer’s location. We find that plasma lensing and scintillation can result in a narrow bandwidth in the observed spectrum. However, the likelihood of these phenomena being responsible for the narrow observed spectra with Δν/ν 0 < 0.58 in the fairly large observed sample of FRBs is exceedingly small.

Modeling the dispersion measure—redshift relation for fast radio bursts

This theoretical work investigates different models to predict the redshift of fast radio bursts (FRBs) from their observed dispersion measure (DM) and other reported properties. We performed an extended revision of the FRBs with confirmed galaxy hosts in the literature and built the most updated catalog to date. With this sample of FRBs, we propose four models that relate the DM and z: a linear trend (inspired by the Macquart relation), a log-parabolic function, a power law, and an interpolation for DM that includes z and the position of the host galaxy of the transient. The latter model has the highest success rate according to the metrics implemented: likelihood, median of the z difference, and the Akaike and Bayesian information criteria. Although the performance of model D is closely followed by the power law and linear models, the former has the advantage of accounting for anisotropies in the dispersion measure due to the angular coordinates. Conversely, the log-parabolic formula performs poorly in this task but provides a good prediction for FRBs with low DM at a low redshift. Additionally, we use the reported galaxy properties of the hosts to establish a connection between the observed DM with the star formation rate (SFR) and stellar mass (Ms) of the galaxies where the FRBs reside. In both cases, we find a weak correlation. Although the studied correlations are well-motivated, the sample of FRBs is not statistically significant enough to draw solid conclusions in this second part of our work. With the advent of new facilities devoted to studying the localization and nature of these transients, we will get access to new data that will enrich the proposed models and give us hints on the astrophysical origin and evolution of FRBs.

Deep Synoptic Array Science: First FRB and Host Galaxy Catalog

Fast radio bursts (FRBs) are a powerful and mysterious new class of transients that are luminous enough to be detected at cosmological distances. By associating FRBs to host galaxies, we can measure intrinsic and environmental properties that test FRB origin models, in addition to using them as precise probes of distant cosmic gas. The Deep Synoptic Array (DSA-110) is a radio interferometer built to maximize the rate at which it can simultaneously detect and localize FRBs. Here, we present the first sample of FRBs and host galaxies discovered by the DSA-110. This sample of 11 FRBs is the largest, most uniform sample of localized FRBs to date, as it is selected based on association with host galaxies identified in optical imaging by Pan-STARRS1. These FRBs have not been observed to repeat, and their radio properties (dispersion, temporal scattering, energy) are similar to that of the known nonrepeating FRB population. Most host galaxies have ongoing star formation, as has been identified before for FRB hosts. Two hosts of the new sample are massive, quiescent galaxies. The distribution of star formation history across this host-galaxy sample shows that the delay time distribution is wide, with a power-law model that spans from ∼100 Myr to ≳2 Gyr. This requires the existence of one or more progenitor formation channels associated with old stellar populations, such as the binary evolution of compact objects.

A sample of fast radio bursts discovered and localized with MeerTRAP at the MeerKAT telescope

ABSTRACT We present a sample of well-localized fast radio bursts (FRBs) discovered by the MeerTRAP project at the MeerKAT telescope in South Africa. We discovered the three FRBs in single coherent tied-array beams and localized them to an area of ∼1 arcmin2. We investigate their burst properties, scattering, repetition rates, and localizations in a multiwavelength context. FRB 20201211A shows hints of scatter broadening but is otherwise consistent with instrumental dispersion smearing. For FRB 20210202D, we discovered a faint post-cursor burst separated by ∼200 ms, suggesting a distinct burst component or a repeat pulse. We attempt to associate the FRBs with host galaxy candidates. For FRB 20210408H, we tentatively (0.35–0.53 probability) identify a compatible host at a redshift ∼0.5. Additionally, we analyse the MeerTRAP survey properties, such as the survey coverage, fluence completeness, and their implications for the FRB population. Based on the entire sample of 11 MeerTRAP FRBs discovered by the end of 2021, we estimate the FRB all-sky rates and their scaling with the fluence threshold. The inferred FRB all-sky rates at 1.28 GHz are $8.2_{-4.6}^{+8.0}$ and $2.1_{-1.1}^{+1.8} \times 10^3 \: \text{sky}^{-1} \: \text{d}^{-1}$ above 0.66 and 3.44 Jy ms for the coherent and incoherent surveys, respectively. The scaling between the MeerTRAP rates is flatter than at higher fluences at the 1.4σ level. There seems to be a deficit of low-fluence FRBs, suggesting a break or turn-over in the rate versus fluence relation below 2 Jy ms. We speculate on cosmological or progenitor-intrinsic origins. The cumulative source counts within our surveys appear consistent with the Euclidean scaling.

Subarcminute Localization of 13 Repeating Fast Radio Bursts Detected by CHIME/FRB

We report on improved sky localizations of 13 repeating fast radio bursts (FRBs) discovered by CHIME/FRB via the use of interferometric techniques on channelized voltages from the telescope. These so-called “baseband localizations” improve the localization uncertainty area presented in past studies by more than three orders of magnitude. The improved localization regions are provided for the full sample of FRBs to enable follow-up studies. The localization uncertainties, together with the limits on the source distances from their dispersion measures, allow us to identify likely host galaxies for two of the FRB sources. FRB 20180814A lives in a massive passive red spiral at z ∼ 0.068 with very little indication of star formation, while FRB 20190303A resides in a merging pair of spiral galaxies at z ∼ 0.064 undergoing significant star formation. These galaxies show very different characteristics, further confirming the presence of FRB progenitors in a variety of environments even among the repeating subclass.

Hints of a universal width–energy relation for classified fast radio bursts

The total available sample of fast radio bursts (FRBs) has been growing steadily in recent years, facilitating the study of FRBs from a statistical point of view. At the same time, the classification of FRBs is currently an imperative issue. We propose that the brightness temperature of bursts can serve as an ideal criterion for classification. In this work, we gather the available data for all localized FRBs and we find a positive relation between the intrinsic pulse width and burst energy, Ti ∝ Eν0.25, for three repeating FRBs that is similar to that of our previous work using FRB 20121102A data alone. The critical line TB, cri is found to vary for different FRBs, which may reflect the differences in source properties. This relation can put strong constraints on mainstream radiation mechanisms. It is evident that neither the coherent curvature radiation or synchrotron maser radiation have the capability to reach the high brightness temperature required to reproduce this relation.

Search for Coincident Gravitational-wave and Fast Radio Burst Events from 4-OGC and the First CHIME/FRB Catalog

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 GW candidates have been identified. Binary neutron star (BNS) mergers can produce GWs and short-gamma-ray bursts, as confirmed by GW170817/GRB 170817A. There may be electromagnetic counterparts recorded in archival observations associated with subthreshold GW candidates. The CHIME/FRB Collaboration has reported the first large sample of fast radio bursts (FRBs), millisecond radio transients detected up to cosmological distances; a fraction of these may be associated with BNS mergers. This work searches for coincident GWs and FRBs from BNS mergers using candidates from the fourth Open Gravitational-wave Catalog and the first CHIME/FRB catalog. We use a ranking statistic for GW/FRB association that combines the GW detection statistic with the odds of temporal and spatial association. We analyze GW candidates and nonrepeating FRBs from 2019 April 1 to 2019 July 1, when both the Advanced LIGO/Virgo GW detectors and the CHIME radio telescope were observing. The most significant coincident candidate has a false alarm rate of 0.29 per observation time, which is consistent with a null observation. The null results imply, at most, – of FRBs are produced promptly from the BNS mergers.

Fast radio burst distributions consistent with the first CHIME/FRB catalog

Currently, fast radio bursts (FRBs) have become a very active field in astronomy and cosmology. However, the origin of FRBs is still unknown to date. The studies on the intrinsic FRB distributions might help us to reveal the possible origins of FRBs, and improve the simulations for FRB cosmology. Recently, the first CHIME/FRB catalog of 536 events was released. Such a large uniform sample of FRBs detected by a single telescope is very valuable to test the FRB distributions. Later, it has been claimed that the FRB distribution model tracking the cosmic star formation history (SFH) was rejected by the first CHIME/FRB catalog. In the present work, we consider some empirical FRB distribution models, and find that many of them can be fully consistent with the CHIME/FRB observational data for some suitable model parameters. Notice that a suppressed evolution with respect to SFH is commonly found for FRBs. In particular, we independently confirm that the FRB distribution model tracking SFH can be rejected at very high confidence. On the other hand, all the "successful" models effectively require a certain degree of "delay" with respect to SFH. These results might shed light on the origin of FRBs and FRB cosmology.

Energy and Waiting Time Distributions of FRB 121102 Observed by FAST

Abstract The energy and waiting time distributions are important properties for understanding the physical mechanism of repeating fast radio bursts (FRBs). Recently, the Five-hundred-meter Aperture Spherical radio Telescope (FAST; Nan et al. 2011; Li et al. 2018) detected the largest burst sample of FRB 121102, containing 1652 bursts Li et al. (2021a) We use this sample to investigate the energy and waiting time distributions. The energy count distribution dN/dE at the high-energy range (&gt;1038 erg) can be fitted with a single power-law function with an index of − 1.86 − 0.02 + 0.02 , while the distribution at the low-energy range deviates from the power-law function. An interesting result of Li et al. (2021a) is that there is an apparent temporal gap between early bursts (occurring before MJD 58740) and late bursts (occurring after MJD 58740). We find that the energy distributions of high-energy bursts at different epochs are inconsistent. The power-law index is − 1.70 − 0.03 + 0.03 for early bursts and − 2.60 − 0.14 + 0.15 for late bursts. For bursts observed in a single day, a linear repetition pattern is found. We use the Weibull function to fit the distribution of waiting time of consecutive bursts. The shape parameter k = 0.72 − 0.01 + 0.01 and the event rate r = 736.43 − 28.90 + 26.55 day−1 are derived. If the waiting times with δ t &lt; 28 s are excluded, the burst behavior can be described by a Poisson process. The best-fitting values of k are slightly different for low-energy (E &lt; 1.58 × 1038 erg) and high-energy (E &gt; 1.58 × 1038 erg) bursts.

Constraints on the engines of fast radio bursts

ABSTRACT We model the sample of fast radio bursts (FRBs), including the newly discovered CHIME repeaters, using the decelerating synchrotron maser blast wave model of Metzger, Margalit &amp; Sironi (2019), which built on earlier work by Lyubarsky (2014), Beloborodov (2017). This model postulates that FRBs are precursor radiation from ultrarelativistic magnetized shocks generated as flare ejecta from a central engine collides with an effectively stationary external medium. Downward drifting of the burst frequency structure naturally arises from the deceleration of the blast wave coupled with the dependence of the maser spectral energy distribution, and induced Compton scattering depth, on the upstream medium. The data are consistent with FRBs being produced by flares of energy Eflare ∼ 1043–1046(fξ/10−3)−4/5 erg, where fξ is the maser efficiency, and minimum bulk Lorentz factors Γ ≈ 102–103, which generate the observed FRBs at shock radii rsh ∼ 1012–1013 cm. We infer upstream densities next(rsh) ∼ 102–104 cm−3 and radial profiles next ∝ r−k showing a range of slopes k ≈ [ − 2, 1] (which are seen to evolve between bursts), both broadly consistent with the upstream medium being the inner edge of an ion-loaded shell released by a recent energetic flare. The burst time-scales, energetics, rates, and external medium properties are consistent with repeating FRBs arising from young, hyperactive flaring magnetars, but the methodology presented is generally applicable to any central engine which injects energy impulsively into a dense magnetized medium. Several uncertainties and variations of the model regarding the composition and magnetization of the upstream medium, and the effects of the strong electric field of the FRB wave (strength parameter a ≫ 1) on the upstream medium and its scattering properties, are discussed. One-dimensional particle-in-cell simulations of magnetized shocks into a pair plasma are presented which demonstrate that high maser efficiency can be preserved, even in the limit a ≫ 1 in which the FRB wave accelerates the upstream electrons to ultrarelativistic speeds.

Reconstructing the fraction of baryons in the intergalactic medium with fast radio bursts via Gaussian processes

Fast radio bursts (FRBs) are a promising new probe for astronomy and cosmology. Thanks to their extragalactic and cosmological origin, FRBs could be used to study the intergalactic medium (IGM) and the cosmic expansion. It is expected that numerous FRBs with identified redshifts will be available in the near future through the identification of their host galaxies or counterparts. DMIGM, the contribution from IGM to the observed dispersion measure (DM) of FRB, carries the key information about IGM and the cosmic expansion history. We can thus study the evolution of the universe by using FRBs with identified redshifts. In the present work, we are interested in the fraction of baryon mass in the IGM, fIGM, which is useful to study the cosmic expansion and the problem of the “ missing baryons ”. We propose to reconstruct the evolution of fIGM as a function of redshift z with FRBs via a completely model-independent method, namely Gaussian processes. Since there is not a large sample of FRBs with identified redshifts, we use simulated FRBs instead. Through various simulations, we show that this methodology works well.

Cosmology-independent Estimate of the Fraction of Baryon Mass in the IGM from Fast Radio Burst Observations

Abstract The excessive dispersion measure (DM) of fast radio bursts (FRBs) has been proposed to be a powerful tool to study intergalactic medium (IGM) and to perform cosmography. One issue is that the fraction of baryons in the IGM, f IGM, is not properly constrained. Here, we propose a method of estimating f IGM using a putative sample of FRBs with the measurements of both DM and luminosity distance d L. The latter can be obtained if the FRB is associated with a distance indicator (e.g., a gamma-ray burst or a gravitational-wave event), or the redshift z of the FRB is measured and d L at the corresponding z is available from other distance indicators (e.g., SNe Ia) at the same redshift. As d L/DM essentially does not depend on cosmological parameters, our method can determine f IGM independent of cosmological parameters. We parameterize f IGM as a function of redshift and model the DM contribution from a host galaxy as a function of star formation rate. Assuming f IGM has a mild evolution with redshift with a functional form and by means of Monte Carlo simulations, we show that an unbiased and cosmology-independent estimate of the present value of f IGM with a ∼12% uncertainty can be obtained with 50 joint measurements of d L and DM. In addition, such a method can also lead to a measurement of the mean value of DM contributed from the local host galaxy.

Fast radio bursts from primordial black hole binaries coalescence

In this paper we propose the model that the coalescence of primordial black holes (PBHs) binaries with equal mass $M \sim 10^{28}$g can emit luminous gigahertz (GHz) radio transient, which may be candidate sources for the observed fast radio bursts (FRBs), if at least one black hole holds appropriate amount of net electric charge $Q$. Using a dimensionless quantity for the charge $q = Q/\sqrt{G}M$, our analyses infer that $q\sim O(10^{-4.5})$ can explain the FRBs with released energy of order $O(10^{40}) {\rm ergs}$. With the current sample of FRBs and assuming a distribution of charge $\phi(q)$ for all PBHs, we can deduce that its form is proportional to $q^{-3.0\pm0.1}$ for $q\geq 7.2\times10^{-5}$ if PBHs are sources of the observed FRBs. Furthermore, with the proposed hypothetical scenario and by estimating the local event rate of FRBs $\sim 2.6 \times 10^3 {\rm Gpc}^{-3} {\rm yr}^{-1}$, one derives a lower bound for the fraction of PBHs (at the mass of $10^{28}$g) against that of matter $f_{\rm PBH}(10^{28}{\rm g})$ $\gtrsim 10^{-5}$ needed to explain the rate. With this inspiring estimate, we expect that future observations of FRBs can help to falsify their physical origins from the PBH binaries coalescences. In the future, the gravitational waves produced by mergers of small black holes can be detected by high frequency gravitational wave detectors. We believe that this work would be a useful addition to the current literature on multimessenger astronomy and cosmology.

EXTRACTING HOST GALAXY DISPERSION MEASURE AND CONSTRAINING COSMOLOGICAL PARAMETERS USING FAST RADIO BURST DATA

ABSTRACT The excessive dispersion measures (DMs) and high Galactic latitudes of fast radio bursts (FRBs) hint toward a cosmological origin of these mysterious transients. Methods of using measured DM and redshift z to study cosmology have been proposed, but one needs to assume a certain amount of DM contribution from the host galaxy ( ) in order to apply those methods. We introduce a slope parameter (where is the observed DM subtracting the Galactic contribution), which can be directly measured when a sample of FRBs have z measured. We show that can be roughly inferred from β and the mean values, and , of the sample. Through Monte Carlo simulations, we show that the mean value of local host galaxy DM, , along with other cosmological parameters (mass density in the ΛCDM model, and the IGM portion of the baryon energy density ), can be independently measured through Markov Chain Monte Carlo fitting to the data.

Fast radio bursts as giant pulses from young rapidly rotating pulsars

We discuss possible association of fast radio bursts (FRBs) with supergiant pulses emitted by young pulsars (ages $\sim$ tens to hundreds of years) born with regular magnetic field but very short -- few milliseconds -- spin periods. FRBs are extra-Galactic events coming from distances $d \lesssim 100$ Mpc. Most of the dispersion measure (DM) comes from the material in the freshly ejected SNR shell; for a given burst the DM should decrease with time. FRBs are not expected to be seen below $\sim 300 $ MHz due to free-free absorption in the expanding ejecta. A supernova might have been detected years before the burst; FRBs are mostly associated with star forming galaxies. The model requires that some pulsars are born with very fast spins, of the order of few milliseconds. The observed distribution of spin-down powers $\dot{E}$ in young energetic pulsars is consistent with equal birth rate per decade of $\dot{E}$. Accepting this injection spectrum and scaling the intrinsic brightness of FRBs with $\dot{E}$, we predict the following properties of a large sample of FRBs: (i) the brightest observed events come from a broad distribution in distances; (ii) for repeating bursts brightness either remains nearly constant (if the spin-down time is longer than the age of the pulsar) or decreases with time otherwise; in the latter case DM $\propto \dot{E}$.

PROBING THE INTERGALACTIC MEDIUM WITH FAST RADIO BURSTS

The recently discovered fast radio bursts (FRBs), presumably of extra-galactic origin, have the potential to become a powerful probe of the intergalactic medium (IGM). We point out a few such potential applications. We provide expressions for the dispersion measure and rotation measure as a function of redshift, and we discuss the sensitivity of these measures to the HeII reionization and the IGM magnetic field. Finally we calculate the microlensing effect from an isolate, extragalctic stellar-mass compact object on the FRB spectrum. The time delays between the two lensing images will induce constructive and destructive interference, leaving a specific imprint on the spectra of FRBs. With a high all-sky rate, a large statistical sample of FRBs is expected to make these applications feasible.