Keane et al. recently detected a fading radio source following FRB 150418, leading to the identification of a putative host galaxy at $z = 0.492 \pm 0.008$. Assuming that the fading source is the afterglow of FRB 150418, I model the afterglow and constrain the isotropic energy of the explosion to be a few $10^{50}$ erg, comparable to that of a short duration GRB. The outflow may have a jet opening angle of $\sim 0.22$ rad, so that the beaming-corrected energy is below $10^{49}$ erg. The results rule out most FRB progenitor models for this FRB, but may be consistent with either of the following two scenarios. The first scenario invokes a merger of an NS-NS binary, which produced an undetected short GRB and a supra-massive neutron star, which subsequently collapsed into a black hole, probably 100s of seconds after the short GRB. The second scenario invokes a merger of a compact star binary (BH-BH, NS-NS, or BH-NS) system whose pre-merger dynamical magnetospheric activities made the FRB, which is followed by an undetected short GRB-like transient. The gravitational wave (GW) event GW150914 would be a sister of FRB 150418 in this second scenario. In both cases, one expects an exciting prospect of GW/FRB/GRB associations.
We present LOFAR imaging observations from the April/May 2020 active episode of magnetar SGR 1935+2154. We place the earliest radio limits on persistent emission following the low-luminosity fast radio burst FRB 200428 from the magnetar. We also perform an image-plane search for transient emission and find no radio flares during our observations. We examine post-FRB radio upper limits in the literature and find that all are consistent with the multi-wavelength afterglow predicted by the synchrotron maser shock model interpretation of FRB 200428. However, early optical observations appear to ru…
A radio source that faded over six days, with a redshift of $z\approx0.5$ host, has been identified by Keane et al. (2016) as the transient afterglow to a fast radio burst (FRB 150418). We report follow-up radio and optical observations of the afterglow candidate and find a source that is consistent with an active galactic nucleus. If the afterglow candidate is nonetheless a prototypical FRB afterglow, existing slow-transient surveys limit the fraction of FRBs that produce afterglows to 0.25 for afterglows with fractional variation, $m=2|S_1-S_2|/(S_1+S_2)\geq0.7$, and 0.07 for $m\geq1$, at 95…
Recently, Keane et al. reported the discovery of a fading radio transient following FRB 150418, and interpreted it as the afterglow of the FRB. Williams \& Berger, on the other hand, suggested that the radio transient is analogous to a group of variable radio sources, so that it could be a coincident AGN flare in the observational beam of the FRB. A new observation with VLA showed a re-brightening, which is consistent with the AGN picture. Here, using the radio survey data of Ofek et al., we statistically examine the chance coincidence probability to produce an event like the FRB 150418 transi…
A $γ$-ray transient, Swift J0644.5-5111, has been claimed to be associated with FRB 131104. The $γ$-ray energy output is estimated as $E_γ\approx 5\times 10^{51}$\,erg at the nominal $z\approx 0.55$ redshift implied by the dispersion measure of FRB 131104. However, a long-term radio imaging follow-up observations only place an upper limit on the radio afterglow flux of Swift J0644.5-5111. Applying the external shock model, we make a detailed constraint on the afterglow parameters for the FRB 131104/Swift J0644.5-5111 system. We find that for the commonly used microphysics shock parameters (e.g…
Fast Radio Bursts (FRBs) are new transient radio sources discovered recently. Because of the angular resolution restriction in radio surveys, no optical counter part has been identified yet so it is hard to determine the progenitor of FRBs. In this paper we propose to use radio lensing survey to constrain FRB progenitors. We show that, different types of progenitors lead to different probabilities for a FRB to be gravitationally lensed by dark matter halos in foreground galaxies, since different type progenitors result in different redshift distributions of FRBs. For example, the redshift dist…
Binary neutron star (BNS) mergers are one of the proposed origins for both repeating and non-repeating fast radio bursts (FRBs), which associates FRBs with gravitational waves and short gamma-ray bursts (GRBs). In this work, we explore detectability of radio afterglows from BNS mergers and compare it to the observed radio limits on FRB afterglows. We calculate the afterglow flux powered by the two components: a relativistic jet and a slower isotropic ejecta, and quantify the detection probability as a function of the source redshift, observing time, and flux sensitivity. The model parameter di…
We present a generic formalism to constrain the cosmic rate density history and the source luminosity function of FRB progenitors from the statistical properties of the apparent flux density of non-repeating FRBs detected with Parkes. We include the pulse multipath propagation effects to evaluate the flux density distribution for a generalised spatial density model and luminosity function. We perform simulations to investigate the effects of the telescope beam pattern and temporal resolution on the observed flux density. We find that the FRB progenitors are likely to be younger stars with a re…
Multi-band observations of the fast radio burst (FRB) 131104 show that this burst may be associated with a gamma-ray transient entitled Swift J0644.5-5111. Follow-up observations for potential X-ray and radio counterparts of FRB 131104/Swift J0644.5-5111 got null results and provided the upper limits of the emission flux at 5.5 GHz, 7.5 GHz, $U$-band, and X-ray band. By assuming this association and using these upper limits, environmental properties (the fraction of energyin a magnetic field $\varepsilon_{\rm B}$ and the number density $n$) of the progenitor system of FRB 131104/Swift J0644.5-…
The physical origin of fast radio bursts (FRBs) is unknown. Young magnetars born from gamma-ray bursts (GRBs) have been suggested to be a possible central engine of FRBs. We test such a hypothesis by systematically searching for GRB-FRB spatial associations from 110 FRBs and 1440 GRBs. We find that one FRB event, FRB 171209, discovered by the Parkes telescope is spatially coincident with a historical long-duration GRB 110715A at $z=0.82$. The afterglow of GRB 110715A is consistent with being powered by a millisecond magnetar. The extragalactic dispersion measure of FRB 171209 is in excess of t…
With the localization of fast radio bursts (FRBs) to galaxies similar to the Milky Way and the detection of a bright radio burst from SGR J1935+2154 with energy comparable to extragalactic radio bursts, a magnetar origin for FRBs is evident. By studying the environments of FRBs, evidence for magnetar formation mechanisms not observed in the Milky Way may become apparent. In this paper, we use a sample of FRB host galaxies and a complete sample of core-collapse supernova (CCSN) hosts to determine whether FRB progenitors are consistent with a population of magnetars born in CCSNe. We also compar…
We present a new fast radio burst (FRB) at 920 MHz discovered during commensal observations conducted with the Australian Square Kilometre Array Pathfinder (ASKAP) as part of the Commensal Real-time ASKAP Fast Transients (CRAFT) survey. FRB 191001 was detected at a dispersion measure (DM) of 506.92(4) pc cm$^{-3}$ and its measured fluence of 143(15) Jy ms is the highest of the bursts localized to host galaxies by ASKAP to date. The subarcsecond localization of the FRB provided by ASKAP reveals that the burst originated in the outskirts of a highly star-forming spiral in a galaxy pair at redshi…
Some fast radio bursts (FRBs) are expected to be associated with the afterglow emission of gamma-ray bursts (GRBs), while a short-lived, supermassive neutron star (NS) forms during the GRBs. I investigate the possible contributions to the dispersion measure (DM) of the FRBs from the GRB ejecta and the wind blown from the precollapsing NS. On the one hand, sometimes an internal X-ray plateau afterglow could be produced by the NS wind, which indicates that a great number of electron-positron pairs are carried by the wind. If the pair-generation radius satisfies a somewhat rigorous condition, the…
We present the results of a multiwavelength campaign of FRB 20201124A, the third closest repeating fast radio burst recently localized in a nearby (z=0.0978) galaxy. Deep VLA observations led to the detection of quiescent radio emission, also marginally visible in X-rays with Chandra. Imaging at 22 GHz allowed us to resolve the source on a scale of $\gtrsim$ 1 arcsec and locate it at the position of the FRB, within an error of 0.2 arcsec. EVN and e-MERLIN observations sampled small angular scales, from 2 to 100 mas, providing tight upper limits on the presence of a compact source and evidence …
The population of fast radio bursts (FRBs) will continue to diverge into two groups depending on their method of discovery: those which can be localised, and those which cannot. Events potentially less useful for astronomical and cosmological purposes due to limited localisation will accumulate with the advent of new facilities and continued efforts by, e.g., the SUPERB collaboration, which may require afterglows or multi-wavelength counterparts for sub-arcsecond localisation. It is important to exploit these sources to their maximum scientific potential. We perform analysis of FRB dispersion …
Fast Radio Bursts (FRBs) are intense, millisecond-duration broadband radio transients, the emission mechanisms of which are not understood. Masui et al. recently presented Green Bank Telescope observations of FRB 110523, which displayed temporal variation of the linear polarisation position angle (PA). This effect is commonly seen in radio pulsars and is attributed to a changing projected magnetic field orientation in the emission region as the star rotates. If a neutron star is the progenitor of this FRB, and the emission mechanism is pulsar-like, we show that the progenitor is either rapidly…
We investigate the intrinsic properties of a sample of bright (E_iso > 10^52 erg) gamma-ray bursts, comparing those with and without radio afterglows. We find that the sample of bursts with no radio afterglows has a significantly shorter mean intrinsic duration of the prompt gamma-ray radiation, and the distribution of this duration is significantly different from those bursts with a radio afterglow. Although the sample with no radio afterglow has on average lower isotropic energy, the lack of radio afterglow does not appear to be a result of simply energetics of the burst, but a reflection of…
Since the discovery of FRB 200428 associated with the Galactic SGR 1935+2154, magnetars are considered to power fast radio bursts (FRBs). It is widely believed that magnetars could form by core-collapse (CC) explosions and compact binary mergers, such as binary neutron star (BNS), binary white dwarfs (BWD), and neutron star-white dwarf (NSWD) mergers. Therefore, it is important to distinguish the various progenitors. The expansion of the merger ejecta produces a time-evolving dispersion measure (DM) and rotation measure (RM) that can probe the local environments of FRBs. In this paper, we deri…
What the progenitors of fast radio bursts (FRBs) are, and whether there are multiple types of progenitors are open questions. The advent of localized FRBs with host galaxy redshifts allows the various emission models to be directly tested for the first time. Given the recent localizations of two non-repeating FRBs (FRB 180924 and FRB 190523), we discuss a selection of FRB emission models and demonstrate how we can place constraints on key model parameters like the magnetic field strength and age of the putative FRB-emitting neutron star. In particular, we focus on models related to compact bin…
The nature of fast radio bursts (FRBs) remains enigmatic. Highly energetic radio pulses of millisecond duration, FRBs are observed with dispersion measures consistent with an extragalactic source. A variety of models have been proposed to explain their origin. One popular class of theorized FRB progenitor is the coalescence of compact binaries composed of neutron stars and/or black holes. Such coalescence events are strong gravitational-wave emitters. We demonstrate that measurements made by the LIGO and Virgo gravitational-wave observatories can be leveraged to severely constrain the validity…
Dispersion measure (DM) of Fast Radio Bursts (FRBs) are commonly used as a indicator of distance assuming that DM in excess of the expected amount within the Milky Way in the direction of each FRB arise mostly from the inter-galactic medium. However, the assumption might not be true if, for example, most FRB progenitors are embedded in ionized circumstellar material (CSM, e.g. supernova remnant). In this study, we jointly analyze distributions of DM, flux density, and fluence of the FRB samples observed by the Parkes telescope and the Australian Square Kilometre Array Pathfinder (ASKAP) using …
The Australian SKA Pathfinder (ASKAP) telescope has started to localize Fast Radio Bursts (FRBs) to arcsecond accuracy from the detection of a single pulse, allowing their host galaxies to be reliably identified. We discuss the global properties of the host galaxies of the first four FRBs localized by ASKAP, which lie in the redshift range $0.11<z<0.48$. All four are massive galaxies (log( $M_{*}/ M_{\odot}$) $\sim 9.4 -10.4$) with modest star-formation rates of up to $2M_{\odot}$yr$^{-1}$ -- very different to the host galaxy of the first repeating FRB 121102, which is a dwarf galaxy with a hi…
Flux Variations of Fast Radio Bursts and Their Persistent Radio Sources: Evidence for a Shared Progenitor
Central China Normal University（华中师范大学）；Tsinghua University（清华大学）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；The Hong Kong Institute for Astronomy and Astrophysics, The University of Hong Kong（香港大学天体物理研究所）；Department of Physics, The University of Hong Kong（香港大学物理系）；Nevada Center for Astrophysics, University of Nevada, Las Vegas（内华达大学拉斯维加斯分校天体物理中心）；Department of Physics and Astronomy, University of Nevada, Las Vegas（内华达大学拉斯维加斯分校物理与天文系）
The early X-ray afterglows of gamma-ray bursts (GRBs) are usually well described by absorbed power laws. However, in some cases, additional thermal components have been identified. The origin of this emission is debated, with proposed explanations including supernova shock breakout, emission from a cocoon surrounding the jet, as well as emission from the jet itself. A larger sample of detections is needed in order to place constraints on these different models. Here we present a time-resolved spectral analysis of 74 GRBs observed by Swift XRT in a search for thermal components. We report six d…
James Webb Space Telescope Observations of the Nearby and Precisely-Localized FRB 20250316A: A Potential Near-IR Counterpart and Implications for the Progenitors of Fast Radio Bursts
Optical/infrared observations of the extraordinary GRB 250702B: a highly obscured afterglow in a massive galaxy consistent with multiple possible progenitors
本文通过多台望远镜的光学/红外观测研究最长伽马射线暴 GRB 250702B，发现其高度遮蔽的余辉来自相对论性喷流，宿主为正在并合的大质量富尘星系，并指出多种 progenitor 情景均可解释观测结果。
Very recently a fast radio burst (FRB) 200428 associated with a strong X-ray burst from the Galactic magnetar SGR 1935+2154 has been detected, which is direct evidence supporting the magnetar progenitor models of FRBs. Assuming the FRB radiation mechanism is synchrotron maser emission from magnetized shocks, we develop a specific scenario by introducing a density jump structure of upstream medium, and thus the double-peaked character of FRB 200428 is a natural outcome. The luminosity and emission frequency of two pulses can be well explained in this scenario. Furthermore, we find that the sync…
We study thermal emission from circumstellar structures heated by gamma-ray burst (GRB) radiation and ejecta and calculate its contribution to GRB optical and X-ray afterglows using the modified radiation hydro-code small STELLA. It is shown that thermal emission originating in heated dense shells around the GRB progenitor star can reproduce X-ray plateaus (like observed in GRB 050904, 070110) as well as deviations from a power law fading observed in optical afterglows of some GRBs (e.g. 020124, 030328, 030429X, 050904). Thermal radiation pressure in the heated circumburst shell dominates the …
[abridged] We investigate the afterglow properties and large-scale environments of several short-duration gamma-ray bursts (GRBs) with sub-arcsecond optical afterglow positions but no bright coincident host galaxies. The purpose of this joint study is to robustly assess the possibility of significant offsets, a hallmark of the compact object binary merger model. Five such events exist in the current sample of 20 short bursts with optical afterglows, and we find that their optical, X-ray, and gamma-ray emission are systematically fainter. These differences may be due to lower circumburst densit…
Aims: Following the detection of the fast radio burst FRB150418 by the SUPERB project at the Parkes radio telescope, we aim to search for very-high energy gamma-ray afterglow emission. Methods: Follow-up observations in the very-high energy gamma-ray domain were obtained with the H.E.S.S. imaging atmospheric Cherenkov telescope system within 14.5 hours of the radio burst. Results: The obtained 1.4 hours of gamma-ray observations are presented and discussed. At the 99 % C.L. we obtained an integral upper limit on the gamma-ray flux of (E>350 GeV) < 1.33 x 10^-8 m^-2s^-1. Differential flux upper…
GRB 130925A is a peculiar event characterized by an extremely long gamma-ray duration ($\approx$7 ks), as well as dramatic flaring in the X-rays for $\approx$20 ks. After this period, its X-ray afterglow shows an atypical soft spectrum with photon index $Γ$$\sim$4, as observed by Swift and Chandra, until $\approx 10^7$ s, when XMM-Newton observations uncover a harder spectral shape with $Γ$$\sim$2.5, commonly observed in GRB afterglows. We find that two distinct emission components are needed to explain the X-ray observations: a thermal component, which dominates the X-ray emission for several…
With multiple observatories and missions being planned for detecting orphaned afterglows associated with gamma-ray bursts (GRBs) we emphasize the importance of developing data analysis strategies for searching their possible counterpart signals in the data of gravitational wave (GW) detectors in the advanced detector era. This is especially attractive since short hard gamma-ray bursts (SGRBs) may have compact binary coalescences involving neutron stars (CBCNSs) as their progenitors, which emit gravitational waves. Joint electromagnetic (EM) and GW observations of these objects will enrich our …
The identification and localization of Fast Radio Bursts to their host galaxies has revealed important details about the progenitors of these mysterious, millisecond-long bursts of coherent radio emission. In this work we study the most probable host galaxy of the apparently non-repeating CHIME/FRB event FRB 20190425A -- a particularly high luminosity, low dispersion measure event that was demonstrated by Moroianu et al. 2022 to be temporally and spatially coincident with the LIGO-Virgo-KAGRA binary neutron star merger GW190425, suggesting an astrophysical association (p-value 0.0052). In this…
Kilonova and progenitor properties of merger-driven gamma-ray bursts
Goethe Universität Frankfurt（法兰克福歌德大学）；INAF – Osservatorio di Astrofisica e Scienza dello Spazio（意大利国家天体物理研究所天体物理学与空间科学天文台）；INFN – Sezione di Bologna（意大利国家核物理研究所博洛尼部分部）；Nikhef（荷兰国家粒子物理研究所）；Institute for Gravitational and Subatomic Physics (GRASP), Utrecht University（乌得勒支大学引力与亚原子物理研究所）；University of Ferrara（费拉拉大学）；INFN, Sezione di Ferrara（意大利国家核物理研究所费拉拉分部）；INAF – Osservatorio Astronomico d’Abruzzo（意大利国家天体物理研究所阿布鲁佐天文台）；Universita‘ di Napoli Federico II（那不勒斯费德里科二世大学）；INAF – Osservatorio Astronomico di Capodimonte（意大利国家天体物理研究所卡波迪蒙特天文台）
We report the results of our observing campaign on GRB140903A, a nearby (z=0.351) short duration (T90~0.3 s) gamma-ray burst discovered by Swift. We monitored the X-ray afterglow with Chandra up to 21 days after the burst, and detected a steeper decay of the X-ray flux after approximately 1 day. Continued monitoring at optical and radio wavelengths showed a similar decay in flux at nearly the same time, and we interpret it as evidence of a narrowly collimated jet. By using the standard fireball model to describe the afterglow evolution, we derive a jet opening angle of 5 deg and a collimation-…
The peak time of optical afterglow may be used as a proxy to constrain the Lorentz factor Gamma of the gamma-ray burst (GRB) ejecta. We revisit this method by including bursts with optical observations that started when the afterglow flux was already decaying; these bursts can provide useful lower limits on Gamma. Combining all analyzed bursts in our sample, we find that the previously reported correlation between Gamma and the burst luminosity L_gamma does not hold. However, the data clearly shows a lower bound Gamma_min which increases with L_gamma. We suggest an explanation for this feature…
GRB 111209A is the longest ever recorded burst. This burst was detected by Swift and Konus-Wind, and we obtained TOO time from XMM-Newton as well as prompt data from TAROT. We made a common reduction using data from these instruments together with other ones. This allows for the first time a precise study at high signal-to-noise ratio of the prompt to afterglow transition. We show that several mechanisms are responsible of this phase. In its prompt phase, we show that its duration is longer than 20 000 seconds. This, combined with the fact that the burst fluence is among the top 5% of what is …
The possibility to divide GRBs in different subclasses allow to understand better the physics underlying their emission mechanisms and progenitors. The induced gravitational collapse scenario proposes a binary progenitor to explain the time-sequence in GRBs-SNe. We show the existence of a common behavior of the late decay of the X-ray afterglow emission of this subclass of GRBs, pointing to a common physical mechanism of their late emission, consistent with the IGC picture.
The "ultra-long" Gamma Ray Burst GRB 111209A at redshift z=0.677, is so far the longest GRB ever observed, with rest frame prompt emission duration of ~4 hours. In order to explain the bursts exceptional longevity, a low metallicity blue supergiant progenitor has been invoked. In this work, we further investigate this peculiar burst by performing a multi-band temporal and spectral analysis of both the prompt and the afterglow emission. We use proprietary and publicly available data from Swift, Konus Wind, XMM-Newton, TAROT as well as from other ground based optical and radio telescopes. We fin…
We present the prompt BAT and afterglow XRT data of Swift-discovered GRB081109A up to ~ 5\times 10^5 sec after the trigger, and the early ground-based optical follow-ups. The temporal and spectral indices of the X-ray afterglow emission change remarkably. We interpret this as the GRB jet first traversing the freely expanding supersonic stellar wind of the progenitor with density varying as $ρ\propto r^{-2}$. Then after approximately 300 sec the jet traverses into a region of apparent constant density similar to that expected in the stalled-wind region of a stellar wind bubble or the interstell…
We study the > 10 ratios in the X-ray to optical column densities inferred from afterglow spectra of Gamma Ray Bursts due to gas surrounding their progenitors. We present time-evolving photoionization calculations for these afterglows and explore different conditions for their environment. We find that homogenous models of the environment (constant density) predict X-ray columns similar to those found in the optical spectra, with the bulk of the opacity being produced by neutral material at large distances from the burst. This result is independent of gas density or metallicity. Only models as…
Fast Radio Bursts Trace Cosmic Star Formation with Little Delay
Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台暗物质与空间天文重点实验室）；School of Astronomy and Space Science, University of Science and Technology of China（中国科学技术大学天文与空间科学学院）
