While gamma-ray bursts (GRBs) were once believed to be a dominant source of astrophysical neutrinos, the lack of any significant correlation between high-energy photons and neutrinos has resulted in stringent limits on their neutrino fluxes. Previous IceCube searches for neutrinos from GRBs have generally focused on the prompt phase of GRBs. However, the higher density during the GRB precursor stage could lead to more hadronic interactions, and therefore be the predominant time of neutrino emission. We present results from an analysis of Fermi-GBM data to identify and characterize individual precursor flashes. Together with an up-to-date catalog of GRBs, we have made our results available via an online tool. An IceCube analysis method to search for neutrinos arriving coincident with GRB precursors has been developed. In this presentation, we compare the sensitivity of this analysis to previous IceCube analyses and discuss the implications in case a significant signal is found.
Gamma-ray bursts (GRBs) are among the most powerful events observed in our universe and have long been considered as possible sources of ultra-high-energy cosmic rays, which makes them promising neutrino source candidates. Previous IceCube searches for neutrino correlations with GRBs focused on the prompt (main emission) phase of the GRB and found no significant correlation between neutrino events and the observed GRBs. This motivates us to extend our search beyond the prompt phase. We perform analyses looking for evidence of neutrino emission up to 14 days before and after the prompt phase of…
On July 31st, 2016, the ICECUBE collaboration reported the detection of a high-energy starting event induced by an astrophysical neutrino. We report here about the search for a gamma-ray counterpart of the ICECUBE-160731 event made with the AGILE satellite. No detection was found spanning the time interval of +/- 1 ks around the neutrino event time T0 using the AGILE "burst search" system. Looking for a possible gamma-ray precursor in the results of the AGILE-GRID automatic Quick Look procedure over predefined 48-hours time-bins, we found an excess above 100 MeV between one and two days before…
Although IceCube has discovered a diffuse astrophysical neutrino flux, the underlying sources of these neutrinos remain unknown. Transient astrophysical objects, such as fast radio bursts (FRBs), could explain a large percentage of the measured flux. We present the analysis techniques of IceCube searches for MeV to TeV neutrinos from FRBs. As no significant correlation between IceCube neutrinos and FRBs has been found, we present the first limit on MeV neutrino emission from FRBs and the most constraining limits for neutrinos with GeV to TeV energies. We also describe the prospects for future …
Jet heating via nuclear collisions may be the main mechanism for gamma-ray burst (GRB) emission. Besides producing the observed gamma-rays, collisional heating must generate 10-100 GeV neutrinos, implying a close relation between the neutrino and gamma-ray luminosities. We exploit this theoretical relation to make predictions for possible GRB detections by IceCube+DeepCore. To estimate the expected neutrino signal, we use the largest sample of bursts observed by BATSE in 1991-2000. A GRB neutrino could have been detected if IceCube+DeepCore operated at that time. Detection of 10-100 GeV neutri…
In this review I discuss the ultra-high energy neutrinos (UHEN) originated from Cosmic-Rays propogation (GZK neutrinos) and from Gamma Ray Bursts (GRBs), and discuss their detectability in kilometers scale detectors like ARA and IceCube. While GZK neutrinos are expected from cosmic ray interactions on the CMB, the GRB neutrinos depend on the physics inside the sources. GRBs are predicted to emit UHEN in the prompt and in the later 'after-glow' phase. I discuss the constraints on the hadronic component of GRBs derived from the search of four years of IceCube data for a prompt neutrino fux from …
Since 1997 the neutrino telescope AMANDA at the geographic South Pole has been monitoring our Galaxy for neutrino bursts from supernovae. Triggers were introduced in 2004 to submit burst candidates to the Supernova Early Warning System SNEWS. From 2007 the burst search was extended to the much larger IceCube telescope, which now supersedes AMANDA. By exploiting the low photomultiplier noise in the antarctic ice (on average 280Hz for IceCube), neutrino bursts from nearby supernovae can be identified by the induced collective rise in the pulse rates. Although only a counting experiment, IceCube …
We have analyzed the light curves of 519 short gamma-ray bursts (GRBs) detected in the SPI-ACS/INTEGRAL experiment from December 2002 to May 2014 to search for precursors. Both the light curves of 519 individual events and the averaged light curve of 372 brightest bursts have been analyzed. In a few cases, we have found and thoroughly studied precursor candidates based on SPI-ACS/INTEGRAL, GBM/Fermi, and LAT/Fermi data. A statistical analysis of the averaged light curve for the entire sample of short bursts has revealed no regular precursor. Upper limits for the relative intensity of precursor…
We select 52 long gamma-ray bursts(GRBs) having the precursor activity in the third Swift-BAT catalog. Each episode shown in both the precursors and the main bursts is fitted by the Norris function. We systematically analyze the temporal properties for both the precursors and the main bursts. We do not find any significant difference between the temporal profile of the precursor and that of the main burst. The photon count of the precursor is related to that of the main burst. It is indicated that the precursor and the main burst might have the same physical origin, as the precursor and the ma…
We present an analysis of more than 11 years of Fermi-GBM data in which 217 Gamma-Ray Bursts (GRBs) are found for which their main burst is preceded by a precursor flash. We find that short GRBs ($<$2 s) are ~10 times less likely to produce a precursor than long GRBs. The quiescent time profile is well described by a double Gaussian distribution, indicating that the observed precursors have two distinct physical progenitors. The light curves of the identified precursor GRBs are publicly available in an online catalog (https://icecube.wisc.edu/~grbweb_public/Precursors.html).
We extract 18 candidate short gamma-ray bursts (SGRBs) with precursors from 660 SGRBs observed by {\em Fermi} and {\em Swift} satellites, and carry out a comprehensive analysis on their temporal and spectral features. We obtain the following results: (1) For a large fraction of candidates, the main burst durations are longer than their precursor durations, comparable to their quiescent times from the end of precursors to the beginning of their main bursts. (2) The average flux of precursors tends to increase as their main bursts brighten. (3) As seen from the distributions of hardness ratio an…
We carried out a systematic search of precursors on the sample of short GRBs observed by Swift. We found that ~8-10% of short GRBs display such early episode of emission. One burst (GRB 090510) shows two precursor events, the former ~13 s and the latter ~0.5 s before the GRB. We did not find any substantial difference between the precursor and the main GRB emission, and between short GRBs with and without precursors. We discuss possible mechanisms to reproduce the observed precursor emission within the scenario of compact object mergers. The implications of our results on quantum gravity const…
Pulse-resolved Classification and Characteristics of Long-duration GRBs with \emph{Swift}-BAT Data.I. Precursors versus Main Bursts
Institute of Fundamental Physics and Quantum Technology, Ningbo University（宁波大学基础物理与量子技术研究院）；School of Physical Science and Technology, Ningbo University（宁波大学物理科学与技术学院）；Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台）；School of Astronomy and Space Science, Nanjing University（南京大学天文与空间科学学院）
We consider the possibility of observing supernova (SN) - gamma-ray burst (GRB) pairs separated by several years. These energetic events correspond to the second SN explosion in a double star system followed by the formation of the very short-lived pair of compact objects and finally by the GRB generation after their merge. Possible connection of SN 1997ds and GRB 990425 is discussed.
The next galactic supernova presents a once-in-a-lifetime opportunity to obtain detailed information about the explosion of a star and the extreme conditions found within its core. A core-collapse supernova will produce a neutrino burst visible up to half a day before the electromagnetic radiation from the explosion, so the burst will provide an early warning for optical follow-up. Since local supernovae are exceedingly rare, it is critical that neutrino detectors provide prompt alerts after the arrival of a burst. The IceCube Neutrino Observatory operates with $>99\%$ uptime and is sensitive …
About 15% of Gamma Ray Bursts have precursors, i.e. emission episodes preceding the main event, whose spectral and temporal properties are similar to the main emission. We propose that precursors have their own fireball, producing afterglow emission due to the dissipation of the kinetic energy via external shock. In the time lapse between the precursor and the main event, we assume that the central engine is not completely turned off, but it continues to eject relativistic material at a smaller rate, whose emission is below the background level. The precursor fireball generates a first aftergl…
As evidenced by the coincident detections of GW170817 and GRB 170817A, short gamma-ray bursts are likely associated with neutron star-neutron star merger events. Although rare, some bursts display episodes of early emission, with precursor flares being observed up to $\sim 10$ seconds prior to the main burst. As the stars inspiral due to gravitational wave emission, the exertion of mutual tidal forces leads to the excitation of stellar oscillation modes, which may come into resonance with the orbital motion. Mode amplitudes increase substantially during a period of resonance as tidal energy is…
IceCube has detected many TeV--PeV neutrinos, but their astrophysical origins remain largely unknown. Motivated by the observed late-time X-ray/optical bumps in some gamma-ray bursts (GRBs), we examine the correlation between IceCube neutrinos and GRBs allowing delayed neutrinos $\sim$days after the prompt gamma rays. Although we have not found any definitive correlation, up to $\sim$10\% of the events observed so far at IceCube may have been neutrinos produced by the late-time GRB activities at $\sim$1 day. Assuming a connection between some IceCube events and the late GRB bumps, we show in a…
The fireshell model for Gamma-Ray Bursts (GRBs) naturally leads to a canonical GRB composed of a proper-GRB (P-GRB) and an afterglow. P-GRBs, introduced by us in 2001, are sometimes considered "precursors" of the main GRB event in the current literature. We show in this paper how the fireshell model leads to the understanding of the structure of GRBs, with precise estimates of the time sequence and intensities of the P-GRB and the of the afterglow. It leads as well to a natural classification of the canonical GRBs which overcomes the traditional one in short and long GRBs.
The precursors of short and long Gamma Ray Bursts (SGRBs and LGRBs) can serve as probes of their progenitors, as well as shedding light on the physical processes of mergers or core-collapse supernovae. Some models predict the possible existence of Quasi-Periodically Oscillations (QPO) in the precursors of SGRBs. Although many previous studies have performed QPO search in the main emission of SGRBs and LGRBs, so far there was no systematic QPO search in their precursors. In this work, we perform a detailed QPO search in the precursors of SGRBs and LGRBs detected by Fermi/GBM from 2008 to 2019 u…
We present a search for neutrinos in coincidence in time and direction with four fast radio bursts (FRBs) detected by the Parkes and Green Bank radio telescopes during the first year of operation of the complete IceCube Neutrino Observatory (May 2011 through May 2012). The neutrino sample consists of 138,322 muon neutrino candidate events, which are dominated by atmospheric neutrinos and muons but also contain an astrophysical neutrino component. Considering only neutrinos detected on the same day as each FRB, zero IceCube events were found to be compatible with the FRB directions within the e…
The probability of observing "supernova - gamma-ray burst" (GRB) pair events and recurrent GRBs from one galaxy in a time interval of several years has been estimated. Supernova explosions in binary systems accompanied by the formation of a short-lived pair of compact objects can be the sources of such events. If a short GRB is generated during the collision of a pair, then approximately each of ~300 short GRBs with redshift z must have an optical precursor - a supernova in the observer's time interval <2(1+z)yr. If the supernova explosion has the pattern of a hypernova, then a successive obse…
We present the results of searches for high-energy muon neutrinos from 41 gamma-ray bursts (GRBs) in the northern sky with the IceCube detector in its 22-string configuration active in 2007/2008. The searches cover both the prompt and a possible precursor emission as well as a model-independent, wide time window of -1 h to +3 h around each GRB. In contrast to previous searches with a large GRB population, we do not utilize a standard Waxman-Bahcall GRB flux for the prompt emission but calculate individual neutrino spectra for all 41 GRBs from the burst parameters measured by satellites. In non…
The increasingly deep limit on the neutrino emission from gamma-ray bursts (GRBs) with IceCube observations has reached the level that could put useful constraints on the fireball properties. We first present a revised analytic calculation of the neutrino flux, which predicts a flux an order of magnitude lower than that obtained by the IceCube collaboration. For benchmark model parameters (e.g. the bulk Lorentz factor is Γ=10^{2.5}, the observed variability time for long GRBs is t_v=0.01 s and the ratio between the energy in accelerated protons and in radiation is η_p=10 for every burst) in th…
The recently discovered peculiar gamma-ray burst GRB 200826A poses a dilemma for the collapsar model. Although all other characteristics of the burst are consistent with it being a Type II (i.e., collapse of a massive star) event, the observed duration of the event is only approximately 1 s, which is at odds with the predicted allowable timescale range for a collapsar event. To resolve this dilemma, this {\it Letter} proposes that the original burst could be an intrinsically long GRB comprising of a precursor and a main emission (ME) phase. However, the main emission phase is missed due to eit…
The increasing statistics of the high-energy neutrino flux observed by the IceCube Observatory points towards an excess of events above the atmospheric neutrino background in the 30--400 TeV energy range. Such an excess is compatible with the findings of the ANTARES Telescope and it would naturally imply the possibility that more than one source class contributes to the observed flux. Electromagnetically hidden sources have been invoked to interpret this excess of events at low energies. By adopting a unified model for the electromagnetically bright and choked gamma-ray bursts and taking into …
We study GRB 221009A, the brightest gamma-ray burst in the history of observations, using Fermi data. To calibrate them for large inclination angles, we use the Vela X gamma-ray source. Light curves in different spectral ranges demonstrate a 300 s overlap of afterglow and delayed episodes of soft prompt emission. We demonstrate that a relatively weak burst precursor that occurs 3 minutes before the main episode has its own afterglow, i.e., presumably, its own external shock. The main afterglow is the brightest one, includes a photon with an energy of 400 GeV 9 hours after the burst, and is vis…
I present the results of the search for an optical precursor to the naked-eye burst - GRB080319B, which reached 5.87m optical peak luminosity in the "Pi of the Sky" data. A burst of such a high brightness could have been preceded by an optical precursor luminous enough to be in detection range of our experiment. The "Pi of the Sky" cameras observed the coordinates of the GRB for about 20 minutes prior to the explosion, thus provided crucial data for the precursor search. No signal within 3 sigma limit was found. A limit of 12m (V-band equivalent) was set based on the data combined from two cam…
Long duration gamma-ray bursts (GRBs) have often been considered as the natural evolution of some core-collapse supernova (CCSN) progenitors. However, the fraction of CCSNe linked to astrophysical jets and their properties are still poorly constrained. While any successful astrophysical jet harbored in a CCSN should produce high energy neutrinos, photons may be able to successfully escape the stellar envelope only for a fraction of progenitors, possibly leading to the existence of high-luminosity, low-luminosity and not-electromagnetically bright ("choked") GRBs. By postulating a CCSN-GRB conn…
Ultrahigh-energy cosmic rays (UHECRs), if accelerated in the gamma-ray burst (GRB) blastwave, are expected to produce PeV-EeV neutrinos by interacting with long-lived GRB afterglow photons. Detailed spectral and temporal properties of the flux of these neutrinos depend on the GRB blastwave evolution scenario, but can last for days to years time scale in contrast to the seconds to minutes time scale for "burst" neutrino flux contemporaneous with the prompt gamma-ray emission and which has been constrained by IceCube in the $\sim$ 50 TeV-2 PeV range. We compute expected neutrino events in IceCub…
Aims: Gamma Ray Bursts (GRBs) are sometimes preceded by dimmer emission episodes, called "precursors", whose nature is still a puzzle: they could either have the same origin as the main emission episode or they could be due to another mechanism. We investigate if precursors have some spectral distinctive feature with respect to the main GRB episodes. Methods: To this aim we compare the spectral evolution of the precursor with that of the main GRB event. We also study if and how the spectral parameters, and in particular the peak of the vFv spectrum of time resolved spectra, correlates with the…
The upper limit on the flux of ultra high energy neutrinos from gamma-ray bursts (GRBs) that was reported recently by the IceCube collaboration contradicts predictions based on the Fireball model of GRBs, but does not exclude GRBs as a main source of ultra-high energy cosmic rays.
We propose a new way to probe non-standard interactions (NSI) of neutrinos with matter using the ultra-high energy (UHE) neutrino data at current and future neutrino telescopes. We consider the Zee model of radiative neutrino mass generation as a prototype, which allows two charged scalars -- one $SU(2)_L$-doublet and one singlet, both being leptophilic, to be as light as 100 GeV, thereby inducing potentially observable NSI with electrons. We show that these light charged Zee-scalars could give rise to a Glashow-like resonance feature in the UHE neutrino event spectrum at the IceCube neutrino …
We calculate the high energy neutrino spectrum from gamma-ray bursts where the emission arises in a dissipative jet photosphere determined by either baryonically or magnetically dominated dynamics, and compare these neutrino spectra to those obtained in conventional internal shock models. We also calculate the diffuse neutrino spectra based on these models, which appear compatible with the current IceCube 40+59 constraints. While a re-analysis based on the models discussed here and the data from the full array would be needed, it appears that only those models with the most extreme parameters …
We jointly analyze the gamma-ray burst (GRB) data observed with BAT and XRT on board the Swift mission to present a global view on the internal energy dissipation processes in GRBs, including precursors, prompt gamma-ray emission, extended soft gamma-ray emission, and late X-ray flares. The Bayesian block method is utilized to analyze the BAT lightcurves to identify various emission episodes. Our results suggest that these emission components likely share a same physical origin, which is repeated activation of the GRB central engine. What we observe in the gamma-ray band may be the tip-of-iceb…
We study statistical properties of long gamma-ray bursts (GRBs) produced by the collapsing cores of WR stars in binary systems. Fast rotation of the cores enables a two-stage collapse scenario, implying the formation of a spinar-like object. A burst produced by such a collapse consists of two pulses, whose energy budget is enough to explain observed GRBs. We calculate models of spinar evolution using results from a population synthesis of binary systems (done by the `Scenario Machine') as initial parameters for the rotating massive cores. Among the resulting bursts, events with the weaker firs…
Thermonuclear runaway burning of carbon is in rare cases observed from accreting neutron stars as day-long X-ray flares called superbursts. In the few cases where the onset is observed, superbursts exhibit a short precursor burst at the start. In each instance, however, the data was of insufficient quality for spectral analysis of the precursor. Using data from the propane anti-coincidence detector of the PCA instrument on RXTE, we perform the first detailed time resolved spectroscopy of precursors. For a superburst from 4U 1820-30 we demonstrate the presence of photospheric radius expansion. …
At a time when IceCube is nearing completion, we revisit the rationale for constructing kilometer-scale neutrino detectors. We focus on the prospect that such observatories reveal the still-enigmatic sources of cosmic rays. While only a "smoking gun" is missing for the case that the Galactic component of the cosmic-ray spectrum originates in supernova remnants, the origin of the extragalactic component remains a mystery. We speculate on neutrino emission from gamma-ray bursts and active galaxies.
We investigate the prospects of detecting radio afterglows from long Gamma-Ray Bursts (GRBs) from Population III (Pop III) progenitors using the SKA precursor instruments WMA (Murchison Widefield Array) and ASKAP (Australian SKA Pathfinder). We derive a realistic model of GRB afterglows that encompasses the widest range of plausible physical parameters and observation angles. We define the best case scenario of Pop III GRB energy and redshift distributions. Using probability distribution functions fitted to the observed microphysical parameters of long GRBs, we simulate a large number of Pop I…
GRB 221009A is a bright Gamma-ray burst (GRB) with isotropic energy being larger than $10^{54} ~{\rm ergs}$. Its fairly low redshift makes it a promising candidate for high energy neutrino detection. However, a neutrino search for this GRB reported by the IceCube collaboration yielded a null result. In this paper, we utilize the upper limit from IceCube observation to test different GRB prompt emission models. We find that, at least for this specific burst, the dissipative photosphere model could be ruled out in a large parameter space. The internal shock model can survive only with a large bu…
Three-quarters of the 1 cubic kilometer neutrino telescope IceCube is currently taking data. Current models predict high-energy neutrino emission from transient objects like supernovae (SNe) and gammaray bursts (GRBs). To increase the sensitivity to such transient objects we have set up an optical follow-up program that triggers optical observations on multiplets of high-energy muon-neutrinos. We define multiplets as a minimum of two muon-neutrinos from the same direction (within 4 deg) that arrive within a 100 s time window. When this happens, an alert is issued to the four ROTSE-III telescop…
IceCube has measured a diffuse astrophysical flux of TeV-PeV neutrinos. The most plausible sources are unique high energy cosmic ray accelerators like hypernova remnants (HNRs) and remnants from gamma ray bursts in star-burst galaxies, which can produce primary cosmic rays with the required energies and abundance. In this case, however, ordinary supernova remnants (SNRs), which are far more abundant than HNRs, produce a comparable or larger neutrino flux in the ranges up to 100-150 TeV energies, implying a spectral break in the IceCube signal around these energies. The SNRs contribution in the…
The mystery of where and how Nature accelerates the cosmic rays is still unresolved a century after their discovery. Gamma ray bursts (GRBs) have been proposed as one of the more plausible sources of extragalactic cosmic rays. A positive observation of neutrinos in coincidence with a GRB would identify these objects as sources of the highest-energy cosmic rays and provide invaluable information about the processes occurring inside these phenomena. Calculations show that a kilometer-scale neutrino telescope is necessary for this task. The idea of such a detector is now becoming reality as IceCu…
The IceCube detector, which is embedded in the glacial ice at the geographic South Pole, is the first neutrino telescope to comprise a volume of one cubic kilometer. The search for neutrinos of astrophysical origin is among the primary goals of IceCube. Point source candidates include Galactic objects such as supernova remnants (SNRs) as well as extragalactic objects such as Active Galactic Nuclei (AGN) and Gamma-Ray Bursts (GRBs). Offline and online searches for transient sources like GRBs and supernovae (SNe) are presented. Triggered searches use satellite measurements from Fermi, SWIFT and …
Magnetar bursts can be emitted by Alfvén waves growing in the outer magnetosphere to nonlinear amplitudes, $δB/B\sim 1$, and triggering magnetic reconnection. Similar magnetic flares should occur quasi-periodically in a magnetized neutron star binary nearing merger. In both cases, fast dissipation in the magnetic flare creates optically thick $e^\pm$ plasma, whose heat capacity is negligible compared with the generated radiation energy. Magnetic dissipation then involves photon viscosity and acts through Compton drag on the plasma bulk motions in the reconnection region. The effective temperat…
Gamma-ray burst sources appear to fulfill all the conditions for being efficient cosmic ray accelerators, and being extremely compact, are also expected to produce multi-GeV to PeV neutrinos. I review the basic model predictions for the expected neutrino fluxes in classical GRBs as well as in low luminosity and choked bursts, discussing the recent IceCube observational constraints and implications from the observed diffuse neutrino flux.
In some short gamma-ray bursts, precursor flares occurring $\sim$ seconds prior to the main episode have been observed. These flares may then be associated with the last few cycles of the inspiral when the orbital frequency is a few hundred Hz. During these final cycles, tidal forces can resonantly excite quasi-normal modes in the inspiralling stars, leading to a rapid increase in their amplitude. It has been shown that these modes can exert sufficiently strong strains onto the neutron star crust to instigate yieldings. Due to the typical frequencies of $g$-modes being $\sim 100\text{ Hz}$, th…
The IceCube Neutrino Observatory is the world's largest neutrino detector, instrumenting a cubic kilometer of ice at the geographic South Pole. The detector probes neutrino energies from GeV to PeV, and collects high statistics neutrino samples by virtue of its extremely large volume. IceCube was designed to detect high-energy neutrinos from potential cosmic ray acceleration sites such as active galactic nuclei, gamma ray bursts and supernova remnants. IceCube announced the detection of a diffuse flux of astrophysical neutrinos in 2013, including the highest energy neutrinos ever detected. Ice…
The IceCube collaboration is building a cubic kilometer scale neutrino telescope at a depth of 2 km at the geographic South Pole, utilizing the clear Antarctic ice as a Cherenkov medium to detect cosmic neutrinos. The IceCube observatory is complemented by IceTop, a square kilometer air shower array on top of the in-ice detector. The construction of the detector is nearly finished with 79 of a planned 86 strings and 73 of 80 IceTop stations deployed. Its completion is expected in the winter 2010/11. Using data from the partially built detector, we present initial results of searches for neutri…
