Abstract
The collapsar model was proposed to explain the long-duration gamma ray bursts (GRBs), while the short GRBs are associated with the mergers of compact objects. In the first case, mainly the energetics of the events is consistent with the proposed progenitor models, while the duration, time variability, as well as the afterglow emission may shed some light on the detailed properties of the collapsing massive stars. In the latter case, the recent discovery of the binary neutron star (NS-NS) merger in the gravitational wave observation made by LIGO (GW170817) and the detection of associated electromagnetic counterparts, for the first time, gave a direct proof of the NS-NS merger being a progenitor of a short GRB. In general, all GRBs are believed to be powered by accretion through a rotationally supported torus, or by fast rotation of a compact object. For long ones, the rotation of the progenitor star is a key property in order to support accretion over relatively long activity periods and also to sustain the rotation of the black hole itself. The latter is responsible for ejection of the relativistic jets, which are powered due to the extraction of the BH rotational energy, mitigated by the accretion torus, and magnetic fields. The jets must break through the stellar envelope though, which poses a question on the efficiency of this process. Similar mechanisms of powering the jet ejection may act in short GRBs, which in this case may freely propagate through the interstellar medium. The power of the jets launched from the rotating black hole is at first associated mostly with the magnetic Poynting flux, and then, at large distances it is transferred to the kinetic and finally radiative energy of the expanding shells. Beyond the radiative processes expected to take place in the jet propagation phase after the stellar envelope crossing, the significant fraction of the jet acceleration is expected to take place inside the stellar envelope and just right after it in the case of a significant decrease of the exterior pressure support. The implications of the hot cocoon formed during the penetration of the stellar body and the interaction of the outflow with the surrounding material are crucial not only for the outflow collimation but also provide specific observational imprints with most notorious observed panchromatic break in the afterglow lightcurves. Thus a significant number of models have been developed for both matter and Poynting dominated otuflows. In this chapter, we discuss these processes from the theoretical point of view and we highlight the mechanisms responsible for the ultimate production of electromagnetic transients called GRBs. We also speculate on the possible GRB-GW associacion scenarios. Finally, in the context of the recently discovered short GRB and its extended multiwalength emission, we present a model that connects the neutron-rich ejecta launched from the accreting torus in the GRB engine with the production of the unstable heavy isotopes produced in the so-called r-process. The radioactive decay of these isotopes is the source of additional emission observed in optical/infrared wavelengths and was confirmed to be found in a number of sources.
Keywords
- gamma ray burst: general
- black hole physics
- accretion
- accretion disks
- gravitational waves
- neutrinos
- nuclear reactions
- nucleosynthesis
- abundances
1. Introduction
Gamma ray bursts are single, transient, short-lasting events (from a fraction of a second up to around a thousand seconds), and detected on the gamma ray sky. They are typically in the range between 10 keV and 20 MeV and are isotropically distributed on the celestial sphere, while they can occur at random directions, even a few times per day [1]. They are also often accompanied by an optical counterpart, late time X-ray signal, and the afterglow, which lasts for many days after the prompt phase and are detected in lower energies, down to the radio band.
The observed properties and energetics of gamma ray bursts has proven that at their hearts there is a cosmic explosion of an enormous power, which is definitely connected with the birth of compact stars. The newly born black hole is swallowing an extremely large amount of matter in a very short time. The accompanying process of ejection of rarefied and fast streams of plasma, which expand in the interstellar medium with a velocity close to the speed of light, is responsible for the gamma ray emission.
1.1. History of GRBs observations
Gamma ray bursts have been first detected in the 1960s. The original measurement was by chance made by the US military service that operated the satellite Vela. The discovery was published in the Astrophysical Journal much later [2]. The authors of this work refer to the old hypothesis [3] that the supernova explosions should be accompanied by the gamma and X-ray emission. Nevertheless, for the confirmation of the supernova-GRB connection, astronomers had to wait more than 30 years more. Since 1970s, it was already known that GRBs are cosmic events, so that they have been studied by research satellites. The main break through was made in 1990s, when the BATSE satellite confirmed the isotropic distribution of GRBs on the sky. This was a strong argument for their extragalactic origin, and thus GRBs being one of the brightest sources of radiation in the universe. Another achievement of the BATSE mission was to establish two classes of bursts, which statistically cluster around the long (
Until 1997, there were no GRB counterparts found in the lower energy bands. For the first time, the Italian-Dutch satellite BeppoSAX detected the position of a GRB precisely enough, so that the localisation of an optical afterglow was possible for GRB970228 [5]. Here, the name of the GRB identifies the date of its observation, in the format
The host galaxies of GRBs have been identified based on their precise localisations, thanks to
The important discovery which confirmed the origin of GRBs was the detection of emission lines, characteristic for supernova explosion, in the optical afterglows spectra (e.g., GRB030329). Hence, a very strong support was found for the idea of massive star’s explosions being the progenitors of these events [12, 13]. The supernova connection was proposed earlier, since in some of the optical afterglow lightcurves the characteristic red bumps were detected, a few weeks after the GRB [14]. A new era in the GRB studies was opened with the launch of the
In 2008, another high-energy mission was launched,
1.2. Models of GRBs origin
The gamma ray emission originates at rather large distances from the base of the jet. Therefore, the central engine driving the jets and forming its base are hidden from the observer and any studies of its structure must be grounded on the indirect analysis. The signal which would be emitted from the engine could be produced either in gravitational waves or in the neutrinos of MeV energies. Such neutrinos are rather impossible to be detected from cosmological distances. Much more promissing are neutrinos produced in the GRB jets which have energies in the order of GeV [18, 19, 20].
The constraints which are based on the observed isotropic equivalent energy of the bursts suggested that the total energy released during the explosion is in the order of the binding energy of a compact object with a stellar mass:
The burst durations are, however, much longer than the dynamical time, over which the matter can free fall onto such a star. The extended duration of the event must therefore be driven by a viscous process. The most plausible is the disk accretion process, which in addition provides a required collimation of the burst stream along the disk rotation axis. The appearance of a large amount of matter in the vicinity of a black hole, to be accreted with a few tens-hundreds of a second, implies an extremely violent process, most probably a birth of a new black hole.
The scenario of a compact object merger [21] was able to explain the energies required for a detection of the event from a cosmological distance [22]. It was thought first that this scenario could be universal for all the types of GRBs; however, the observations of the GRB host galaxies, their active star formation rates in some cases, and the discoveries of GRB-supernova connection led to a different scenario for the long bursts. The currently accepted scenario for the long GRB progenitor is the
The hypernovae connected with long GRBs are a subgroup of the supernovae type I b/c (which do not exhibit neither hydrogen nor helium lines in their spectra) and constitute about 10% of this class [26]. Statistically, this should agree with the estimated rate of GRBs. Their occurrence rate is about
Among the models proposed to explain the short GRB population, the compact object merger model is most favored. Here, the duration of the event is limited by a much smaller size of the accretion disk, which forms after the remnant matter is left from the disrupted neutron star. The short bursts occur mostly in old, elliptical galaxies and within the regions of low star formation rate [29]. The most probable progenitor configuration is the NS-NS binary; the BH-NS was also studied, see. e.g., Narayan et al. [30]. Alternatively, also the magnetars, being extremely magnetized neutron stars when rotational energy is dissipated on the scale of seconds, may be able to produce Poynting dominated jets and power the GRBs [31].
2. Accretion onto a black hole as a driving engine of a GRB
The accretion tori surrounding black holes are ubiquitous in the universe. They occupy centers of galaxies, or reside in binary systems composed of stellar mass black holes and main sequence stars, being a source of power for their ultraviolet or X-ray emission. In these kinds of objects, frequently the black hole accretion is accompanied with the ejection of jets, launched along the accretion disk axis. Such sources are then observed as the radio-loud quasars, driven by the action of supermassive black holes, or the ‘microquasars’, which are driven by the stellar mass black holes. The jets of plasma are accelerated up to the relativistic speeds, and emit the high-energy radiation, measured over the entire energy spectrum.
Similarly, in the case of ultrarelativistic jets that are sources of gamma rays in GRBs, the driving engine is supposedly the stellar mass black hole surrounded by an accretion disk. However, since the GRB events are transients that last only up to several hundred seconds, and not for thousands, or millions of years, the accretion process should not be persistent and last not too long. The limiting time of the GRB engine activity is governed by the amount of matter available for accretion, and by the rate of this process (Figure 1).
From the computational point of view, the numerical model of any black hole accretion disk is based on standard equations of hydrodynamics (or MHD, if the magnetic fields are taken into account). The global parameters that enter the equations and act as scaling factors are the black hole mass,
2.1. Chemical composition of the accretion disk in GRB engine and the equation of state
The temperature and density in the accretion disk feeding the gamma ray busts are governed by a huge accretion rate. The physical conditions make the disk undergo onset of nuclear reactions, since
Because the plasma may contain a certain number of positrons, which are also a product of the weak processes, the net value of the electron fraction must account for them, and is defined as:
2.2. Neutrino cooling
The neutrino cooling in the GRB central engine is the most efficient mechanism of reducing the thermal energy of the plasma. The radiative processes involving photons are negligibly inefficient due to extremely large optical depths, such that the photons are completely trapped in the plasma.
The neutrino emission results from the following nuclear reactions:
and in certain large parts of the disk these processes lead to a fairly large neutrino emissivities. The equation of state is based on the equilibrium of nuclear reactions, which leads to establishing the balance between the rates of forward and backward processes, and on the ratio of number densities of protons to neutrons [32].
The species in general are relativistic and may have an arbitrary degeneracy level (given by their chemical potential). They are therefore subject to the Fermi-Dirac statistics, as follows from the kinetic theory of gas, and hence the relations between pressure, density, temperature, and entropy in the gas will not obey the ideal gas equation of state. Typically, these quantities are computed numerically and stored in the EOS tables (Figure 2).
2.3. Accretion physics in general relativistic MHD framework
The initial conditions for the structure of accretion disk should be specified in the fixed grid and the background metric most appropriate for the GRB problem is the Kerr spacetime. This is because the black hole is rapidly spinning. The initial condition evolves according to the continuity equation and the energy-momentum conservation equation:
If the magnetic fields are taken into account, the energy tensor contains matter parts and electromagnetic parts:
where
where equation of state of gas in the adiabatic form,
2.4. Nucleosynthesis of heavy isotopes in GRB engines
The subsequent isotopes after Helium are created in the outer layers of the accretion disk body, as well as in its ejecta. Synthesis of heavy isotopes can be computed by means of the thermonuclear reaction network simulations [33]. The code and reaction data (http://webnucleo.org) can be adopted to read the input data in the form of density, temperature, and electron fraction distribution along the distance radial coordinate in the accretion disk [34]. The numerical methods and algorithms in the network computations under the nuclear statistical equilibrium were described in Hix and Meyer [35] (see also Meyer [36] for a review of the r-process nucleosynthesis theory) (Figure 3).
The analysis of the integrated mass fraction distribution allows establishing the role of global parameters of the accretion flow model, such as the black hole mass and its spin, in forming the disk composition. We show here the resulting distribution of certain chosen isotopes synthesized in the nearest vicinity of the accreting black hole (up to
3. Numerical simulations
The modeling of the emerging outflows in both types of GRBs is in general a very difficult task. Beyond the challenges of the various microphysical process participating and the general relativistic frameworks, it involves a wide range of spatial scales. For example, a simulation aimed to describe the whole extent of a jet originating from compact binaries needs a fine resolution of
3.1. Full GRMHD scheme
The merging phase of the compact object binaries has to be performed by fully relativistic schema, that is, ones that beyond capturing the essential of the hydro- and magneto-hydrodynamic aspects of the accretion evolves also the space-time. At present, the ambiguity for the precise nature of the members consisting the binary has not been clarified and the dominant research effort is oriented toward the BH-NS, NS-NS candidates. As a result, a number of codes were developed to solve the underlying equations for both types of progenitors, every of which presenting its own approximations and limitations (see Paschalidis [46] for a list on the codes and a more detailed review on the full GR findings).
Assuming the driving object of the burst is a black hole—torus system simulations must accomplish two challenges: create a viable disk that feeds the system for the burst duration and launch a jet which able to reach the Lorentz factor
which is applicable on
Although the launch of jets was naturally obtained in the fixed space time simulations long before, that task proved to be non-trivial for the full GR ones. The NS-NS simulations by Rezzolla et al. [50] were until recently the only ones that demonstrated the emerging of a jet, while most of the simulations did not show a collimated outflow. For example, the BHNS of Kiuchi et al. [51], a wind was found, but for the NS-NS model of the pressure of the fall back material was so strong preventing even the launching of the wind.
All the above indicates that the magnetic field topology close to the vicinity of the black hole is of crucial importance and no matter of what process (Blandford and Payne [52]) is the one that drives the outflow acceleration and the resulting jet, a large scale poloidal component is crucial to drive the energy outflow outwards. But in the simulations, the field remaining outside the black hole is wounded to a toroidal configuration, while the poloidal component had an alternating orientation. Finally, the launching of the jets in the BHNS framework was achieved once a more realistic bipolar initial configuration was adopted [53]. The realization of such a configuration is a difficult task mostly because of the low density of the exterior medium. By adopting a specific set of initial condition to overcome code limitations on this regime, the authors managed to produce a configuration of enhanced magnetic field over the BH poles because of the magnetic winding. The field strength increased from
4. Ejection and acceleration of jets in gamma ray bursts
In both frameworks of the bursts, the plausible central engine refers to hyperaccreting solar mass black holes surrounded by a massive disk
But beyond the enormous energetic constrains, our mechanism has to face another major challenge, namely, the great variability of the prompt emission lightcurves. Although long debated, two of the most widely accepted models for the origin of the
4.1. Jet launching
The high density and temperature of the accreting flow result in a photon optically thick disk that cannot cool by radiation efficiently. On the other hand, the high temperature and density result in the intense neutrino emission from the inner parts of the disk, called NDAF (neutrino dominated accretion flow). The effects of neutrino outflow, if it is capable to produce a highly relativistic jet and what implications it imposes when it is combined with the Blandford-Znajek process, is a matter of intense debate, presently inconclusive. There exist two critical values of the accretion rate,
where
The total energy ejected in neutrinos was calculated by Zalamea and Beloborodov [61] and in principle can reproduce the GRB energies, but for the higher accretion rates
The other mechanism that accounts for the launch of a low baryon loaded jet is the Blandford-Znajek process that might be resembled with a Penrose proccess of an ideally conducting plasma in the force free limit. According to it, the plasma is pushed via accretion to the ergospheric negative energy orbits, while the magnetic twist results in an outward propagating electromagnetic jet (see Komissarov [68] for an excellent explanation).
In general, the rotational energy of a black hole is
where
where the spin dependent function is properly obtained under full GR framework. A familiar analytical approximation obtained by Lee et al. [69] and Wang et al. [70] is:
where
In the simulations under the fixed Kerr spacetime [71, 73], the central object is fed with a relatively large magnetic flux, that is, more than what the accreting plasma can push inside the horizon. The excessing part of the magnetic flow remains outside the horizon and forms a magnetic barrier [74, 75], saturating accretion and forming a baryon-clean funnel around the axis of rotation (MAD, magnetically-arrested disk). Moreover in some specific initial configuration assumed, the time averaged power of the jet outflow efficiency
4.2. Collimation mechanisms
The effects of the surrounding to the jet material are crucial for the dynamic evolution of the jet affecting both its acceleration and collimation. The build up of a large scale toroidal component in a magnetic dominated jet results to hoop stress that contributes to the jet collimation [76]. Nevertheless, this contribution proves to be less efficient in the relativistic regime and turns to be insufficient even for the cases where a very fast rotation is induced [77, 78, 79]. As a result, the contribution of the exterior environment pressure plays a fundamental role in the GRB outflow evolution for the merging binaries and core-collapsing bursts.
In the long GRB framework, the outflow penetrates the stellar envelope, most likely a Wolf-Rayet star, and continues its propagation to the interstellar space. The propagation of the jet’s head in the dense environment results to sideway motion of the stellar material and to the formation of a hot cocoon surrounding the jet. The accurate description of such a system is cyclic and both jet and stellar material must be described self consistently. The jet velocity depends crucially on the jet cross section, while it determines the amount of energy injected in the cocoon that in its turn defines the supporting exterior pressure of the jet. As a result, there exists a number of numerical simulations investigating the evolution of this phase both of hydrodynamic (e.g., Mizuta and Aloy [80]; Lazzati et al. [81]) as also of magnetic dominated outflows [82]. In addition, theoretical and semi-analytical models have also been developed to interpret the underlying processes (e.g., Bromberg et al. [83]; Globus & Levinson [84]).
The initial propagation, close to the launching point, is similar to the two extreme case of a hydro or Poynting dominated jet since the outflows internal pressure much exceeds the cocoon’s one. The outflow’s freely expansion is up to the collimation point defined by the equality of the above quantities, while after it the outflow evolution differs accordingly to its magnetic context (see Granot et al. [85] for a review). The Poynting dominated outflows result in a faster drilling breakout time in an order of magnitude 0.1 to ~10 s. Bromberg et al. [86] proposed a criterion to identify
5. Radiative processes in jets: emission of gamma rays
Although rich in models, the dynamics of the phase after the jet break out, that is, at the place where the prompt radiation is being produced, is still not well understood. Among the two models assuming matter or Poynting flux dominance, the hot fireball [22, 87] is the older and more widely used one. The matter dominated fireball is mainly constituted by baryons and radiation, with the latter being significantly larger by at least two orders of magnitude. The adiabatic expansion of the fireball accelerates the baryons to high Lorentz factor, while a fraction of this thermal energy is being radiated when the flow becomes transparent to the electron-positron pair creation, providing the so-called photospheric emission. In even higher distances, the outflow inhomogeneities endure mutual collisions leading to the formation of internal shocks that accelerate electrons and produce the non-thermal part of the observed radiation.
The location of the photospheric radius
where
where
Beyond the photospheric emission, the interpretation of the non-thermal prompt emission is much more challenging. Up to day, there is no definite answer for the precise place that the
Lets assume two cells with Lorentz factors
where
where
The observed time variability is given by Kobayashi et al. [92]; Daigne and Mochkovitch [93]; and Kumar and Zhang [72].
where the first term of the right hand is because of the injection time difference and the second because of the shock propagation. We notice that the variability of lightcurves traces in general the central engine activity, and as a result, the high variability of the prompt emission can be ascribed to the intrinsic variability of the source (BH-torus for short bursts, BH-torus plus the propagation inside the star for the long ones).
The biggest problem for the internal shock model is the efficiency of the collisions. The efficiency of the thermal energy production is easily obtained
and is maximized for a given
Despite the great progress in the interpretation of the prompt GRB radiation, crucial issues still remain open and especially on how the mildly relativistic shocks accelerate particles. As a result, today no model that describes self consistently the whole process exists and most of the approach still uses the fractions
6. Multimessanger discoveries of electromagnetic and gravitational wave counterparts
The assembly of black hole binaries detected in gravitational waves by the LIGO interferometer was established since the discovery of GW150914 [101]. These systems contain very massive black holes, whose origin poses a puzzle for the stellar evolution models [102]. One of the possible scenarios for the formation of such a black hole is a process of direct collapse of massive stars. Here, no spectacular hypernova explosion is proposed, and hence no gamma ray burst should have occured during the formation of a very massive black hole neither for the first nor for the second component in the binary. An additional issue is the feedback from a rotationally supported innermost parts of the star during the collapse. It is rather natural that the star at its final stages of evolution should posses some non-negligible angular momentum in the envelope. This angular momentum may, however, help unbind the outer layers and halt accretion (Ramirez-Ruiz 2017, private communication). This will have a consequence for both the ultimate mass of the black hole, and its resultant spin, to be independently verified by the values obtained for these parameters from gravitational waveform constraints.
One of the possibilities when the gravitational wave signal would be found in relation to the rotating massive star collapse, and coincident with a gamma ray burst, was proposed by Janiuk et al. [103]. In this scenatio, the collapse of a massive rotating star in a close binary system with a companion black hole. The primary BH which forms during the core collapse is first being spun up and increases its mass during the fall back of the stellar envelope. As the companion BH enters the outer envelope, it provides an additional angular momentum to the gas. After the infall and spiral-in toward the primary, the two BHs merge inside the circumbinary disk. The second episode of mass accretion and high final spin of the postmerger BH feeds the gamma ray burst.
In the above framework, it is in principle possible that the observed events have two distinct peaks in the electromagnetic signal, separated by the gravitational wave emission. The reorientation of spin vector of the black holes and gravitational recoil of the burst engine is, however, possible. Therefore, the probability of observing two electromagnetic counterparts of the gravitational wave source would be extremely low.
The electromagnetic signal is in general not expected from a BH-BH merger. However, the weak transient detected by Fermi GBM detector 0.4 s after GW 150914 has been generating much speculation [104, 105]. Despite the fact that other gamma ray missions claimed non-detection of the signal, several theoretical scenarios aimed to account for such a coincidence, whether detected, or to be found in the future events [106, 107, 108, 109, 110].
Finally, the binary neutron star merger GW170817, detected in gravitational waves, was connected with the gamma ray emission observed as a weak short burst [111]. Its peculiar properties pose constraints for the progenitor model [112]). Moreover, at lower frequencies, the follow-up surveys have shown the presence of a kilonova emission from the merger’s dynamical ejecta. These ejecta masses are broadly consistent with the estimated r-process production rates, required before to explain the Milky Way isotopes abundances. It is possible that the magnetically driven winds launched due to the accretion in the GRB engine may also contribute to the kilonova emission from NS-NS merger.
7. Summary
Gamma ray bursts are known since almost 50 years now and are still an exciting field of research for both observers and theoretitians. Their energetic requirements proved the fundamental role of the stellar mass black hole formation and mass accretion in the production of ultrarelativistic jets.
The details of this process are, however, far from being fully understood. In short GRBs, the process of black hole birth after the neutron star merger may proceed through different channels, with the possible presence of a transient hypermassive neutron star, depending on the EOS and rotation of the progenitors. In long GRBs, the properties of progenitor star, its envelope rotation, metallicity, etc., as well as the binarity of the whole system, may affect the core collapse in an even greater way. The question of binarity is of a great interest in the context of the fate of high mass X-ray binaries, such as Cygnus X-3, which in addition to the pre-hypernova star contains a companion which is most probably a black hole.
Such fundamental questions are now being attacked with the modern tools of numerical astrophysics, which involve relativistic magnetohydrodynamics and nuclear physics. With the discovery of gravitational waves, a new window has also opened from the observational point of view, especially since the gamma ray signal has been identified in connection with the compact object merger. The identification of the additional electromagnetic signal from the radioactive decay of the GRB ejecta provided a completely new way to probe the whole process and hopefully build a comprehensive picture in the near future.
Acknowledgments
We acknowledge the financial support from the Polish National Science Center through the Grant Sonata-Bis No DEC-2012/05/E/ST9/03914. We also thank the Interdisciplinary Center for Mathematical and Computational Modeling of the Warsaw University for the access to their supercomputing resources, under the grant GB 70-4. Finally, AJ would like to thank the Kavli Summer Program in Astrophysics 2017, and the Center for Transient Astrophysics at the Niels Bohr Institute, for great hospitality and inspiring environment.
References
- 1.
Fishman GJ, Meegan CA. Gamma-Ray Bursts. Annual Review of Astronomy and Astrophysics. 1995; 33 :415 - 2.
Klebesadel RW, Strong IB, Olson RA. Observations of Gamma-Ray Bursts of Cosmic Origin. The Astrophysical Journal. 1973; 182 :(L85) - 3.
Colgate SA. Prompt gamma rays and X-rays from supernovae. Canadian Journal of Physics. 1968; 46 :S476 - 4.
Kouveliotou C et al. Identification of two classes of gamma-ray bursts. The Astrophysical Journal. 1993; 413 :L101 - 5.
Costa E et al. Discovery of an X-ray afterglow associated with the γ-ray burst of 28 February 1997. Nature 1997; 387 :783. astro-ph/9706065 - 6.
Metzger MR et al. Spectral constraints on the redshift of the optical counterpart to the γ-ray burst of 8 May 1997. Nature. 1997; 387 :878 - 7.
Sahu KC et al. The optical counterpart to γ-ray burst GRB970228 observed using the Hubble Space Telescope. Nature. 1997; 387 (476). astro-ph/9705184 - 8.
Djorgovski, SG et al. The cosmic gamma-ray bursts and their host galaxies in a cosmological context. In: Guhathakurta P, editor. Discoveries and Research Prospects from 6-to 10-Meter-Class Telescopes II, Proc. SPIE. 2003; 4834 :238-247. astroph/0301342 - 9.
Frail DA et al. GRB 010222: A Burst within a Starburst. The Astrophysical Journal. 2002; 565 :829. astroph/0108436 - 10.
Porciani C, Madau P. On the Association of Gamma-Ray Bursts with Massive Stars: Implications for Number Counts and Lensing Statistics. The Astrophysical Journal. 2001; 548 :522. astroph/0008294 - 11.
Piran T. The physics of gamma-ray bursts. Reviews of Modern Physics. 2004; 76 :1143. astro-ph/0405503 - 12.
Hjorth J et al. A very energetic supernova associated with the γ-ray burst of 29 March 2003. Nature 2003; 423 :847. astro-ph/0306347 - 13.
Stanek KZ et al. Spectroscopic Discovery of the Supernova 2003dh Associated with GRB 030329. The Astrophysical Journal. 2003; 591 (L17). astro-ph/0304173 - 14.
Bloom JS et al. The unusual afterglow of the γ-ray burst of 26 March 1998 as evidence for a supernova connection. Nature. 1999; 401 :453. astro-ph/9905301 - 15.
Salvaterra R et al. GRB090423 at a redshift of z∼8.1. Nature. 2009; 461 :1258. 0906.1578 - 16.
Guetta D, Piran T. The BATSE-Swift luminosity and redshift distributions of short-duration GRBs. Astronomy and Astrophysics. 2006; 453 :823. astro-ph/0511239 - 17.
Natarajan P et al. The redshift distribution of gamma-ray bursts revisited. Monthly Notices of the Royal Astronomical Society. 2005; 364 :L8. astro-ph/0505496 - 18.
Achterberg A et al., Search for Neutrino-induced Cascades from Gamma-Ray Bursts with AMANDA. The Astrophysical Journal. 2007; 664 (397). astro-ph/0702265 - 19.
Kimura SS, Murase K. Mészáros, P., Kiuchi, K., High-energy Neutrino Emission from Short Gamma-Ray Bursts: Prospects for Coincident Detection with Gravitational Waves. The Astrophysical Journal. 2017; 848 :L4. 1708.07075 - 20.
Paczynski B, Xu G. Neutrino bursts from gamma-ray bursts. The Astrophysical Journal. 1994; 427 :708 - 21.
Eichler D, Livio M, Piran T, Schramm DN. Nucleosynthesis, neutrino bursts and gamma-rays from coalescing neutron stars. Nature. 1989; 340 :126 - 22.
Paczynski B. Gamma-ray bursters at cosmological distances. The Astrophysical Journal. 1986; 308 :(L43) - 23.
Paczyński B. Are Gamma-Ray Bursts in Star-Forming Regions? The Astrophysical Journal. 1998; 494 :L45. astro-ph9710086 - 24.
Woosley SE. Gamma-ray bursts from stellar mass accretion disks around black holes. The Astrophysical Journal. 1993; 405 :273 - 25.
MacFadyen AI, Woosley SE. Collapsars: Gamma-Ray Bursts and Explosions in “Failed Supernovae”. The Astrophysical Journal. 1999; 524 (262). astro-ph/9810274 - 26.
Fryer CL et al. Constraints on Type Ib/c Supernovae and Gamma-Ray Burst Progenitors. Publications of the Astronomical Society of the Pacific. 2007; 119 ;1211. astro-ph/0702338 - 27.
Woosley SE, Bloom JS. The Supernova Gamma-Ray Burst Connection. Annual Review of Astronomy and Astrophysics. 2006; 44 :507. astro-ph/0609142 - 28.
Podsiadlowski P et al. The Rates of Hypernovae and Gamma-Ray Bursts: Implications for Their Progenitors. The Astrophysical Journal. 2004; 607 (L17). astro-ph/0403399 - 29.
Zhang B. Gamma-Ray Bursts in the Swift Era. Chinese J. Astronomy and Astrophysics. 2007; 7 :1. astro-ph/0701520 - 30.
Narayan R, Piran T, Kumar P. Accretion Models of Gamma-Ray Bursts. The Astrophysical Journal. 2001; 557 :949. astro-ph/0103360 - 31.
Usov VV. Millisecond pulsars with extremely strong magnetic fields as a cosmological source of gamma-ray bursts. Nature. 1992; 357 :472 - 32.
Janiuk A. Microphysics in the Gamma-Ray Burst Central Engine. The Astrophysical Journal. 2017; 837 (39):1609.09361 - 33.
Wallerstein G et al. Synthesis of the elements in stars: forty years of progress. Reviews of Modern Physics. 1997; 69 :995 - 34.
Janiuk A. Nucleosynthesis of elements in gamma-ray burst engines, Astronomy and Astrophysics 2014; 568 :A105. 1406.4440 - 35.
Hix WR, Meyer BS. Thermonuclear kinetics in astrophysics. Nuclear Physics A. 2006; 777 :188. astro-ph/0509698 - 36.
Meyer BS. The r-, s-, and p-Processes in Nucleosynthesis. Annual Review of Astronomy and Astrophysics. 1994; 32 :153 - 37.
Banerjee I, Mukhopadhyay B. Nucleosynthesis in the Outflows Associated with Accretion Disks of Type II Collapsars. The Astrophysical Journal. 2013; 778 (8):1309.0954 - 38.
Wu M-R, Ferńandez R, Martínez-Pinedo G, Metzger BD. Production of the entire range of r-process nuclides by black hole accretion disc outflows from neutron star mergers. Monthly Notices of the Royal Astronomical Society. 2016; 463 (3):2323 - 39.
Tanvir NR et al. A ‘kilonova’ associated with the short-duration γ-ray burst GRB 130603B. Nature 2013; 500 :(547). 1306.4971 - 40.
Tanaka M. Kilonova/Macronova Emission from Compact Binary Mergers. Advances in Astronomy. 2016; 2016 :634197. 1605.07235 - 41.
Siegel DM, Metzger BD. Three-Dimensional General-Relativistic Magnetohydrodynamic Simulations of Remnant Accretion Disks from Neutron Star Mergers: Outflows and r-Process Nucleosynthesis. Physical Review Letters. 2017; 119 (23):231102. 1705.05473 - 42.
Zrake J, MacFadyen AI. Magnetic Energy Production by Turbulence in Binary Neutron Star Mergers. The Astrophysical Journal. 2013; 769 (L29). 1303.1450 - 43.
Kiuchi K et al. Efficient magnetic-field amplification due to the Kelvin-Helmholtz instability in binary neutron star mergers. Physical Review D. 2015; 92 (12):124034. 1509.09205 - 44.
Hawley JF, Guan X, Krolik JH. Assessing Quantitative Results in Accretion Simulations: From Local to Global. The Astrophysical Journal. 2011; 738 (84):1103.5987 - 45.
Tchekhovskoy A, McKinney JC, Narayan R. Simulations of ultrarelativistic magneto-dynamic jets from gamma-ray burst engines. Monthly Notices of the Royal Astronomical Society. 2008; 388 (551):0803.3807 - 46.
Paschalidis V. General relativistic simulations of compact binary mergers as engines for short gamma-ray bursts. Classical and Quantum Gravity. 2017; 34 (8):084002. 1611.01519 - 47.
Foucart F. Black-hole-neutron-star mergers: Disk mass predictions. Physical Review D. 2012; 86 (12):124007. 1207.6304 - 48.
Lovelace G et al. Massive disc formation in the tidal disruption of a neutron star by a nearly extremal black hole. Classical and Quantum Gravity 2013; 30 (13):135004. 1302.6297 - 49.
Shibata M, Taniguchi K. Merger of binary neutron stars to a black hole: Disk mass, short gamma-ray bursts, and quasinormal mode ringing. Physical Review D. 2006; 73 (6)064027. astro-ph/0603145 - 50.
Rezzolla L et al. The Missing Link: Merging Neutron Stars Naturally Produce Jet-like Structures and Can Power Short Gamma-ray Bursts. The Astrophysical Journal. 2011; 732 (L6). 1101.4298 - 51.
Kiuchi K et al. High resolution magnetohydrodynamic simulation of black hole-neutron star merger: Mass ejection and short gamma ray bursts. Physical Review D. 2015b; 92 (6):064034. 1506.06811 - 52.
Blandford RD, Payne DG. Hydromagnetic flows from accretion discs and the production of radio jets. Monthly Notices of the Royal Astronomical Society. 1982; 199 :883 - 53.
Paschalidis V, Ruiz M, Shapiro SL. Relativistic Simulations of Black Hole-Neutron Star Coalescence: The Jet Emerges. The Astrophysical Journal. 2015; 806 (L14):1410.7392 - 54.
Ruiz M, Lang RN, Paschalidis V, Shapiro SL. Binary Neutron Star Mergers: A Jet Engine for Short Gamma-Ray Bursts. The Astrophysical Journal. 2016; 824 (L6):1604.02455 - 55.
Blandford RD, Znajek RL. Electromagnetic extraction of energy from Kerr black holes. Monthly Notices of the Royal Astronomical Society. 1977; 179 :433 - 56.
Morsony BJ, Lazzati D, Begelman MC. The Origin and Propagation of Variability in the Outflows of Long-duration Gamma-ray Bursts. The Astrophysical Journal. 2010; 723 (267):1002.0361 - 57.
Zhang B, Yan H. The Internal-collision-induced Magnetic Reconnection and Turbulence (ICMART) Model of Gamma-ray Bursts. The Astrophysical Journal. 2011; 726 (90):1011.1197 - 58.
MacLachlan GA et al. Minimum variability time-scales of long and short GRBs. Monthly Notices of the Royal Astronomical Society. 2013; 432 :857. 1201.4431 - 59.
Shakura NI, Sunyaev RA. Black holes in binary systems. Observational appearance. Astronomy and Astrophysics. 1973; 24 :337 - 60.
Chen, W-X, Beloborodov AM. Neutrino-cooled Accretion Disks around Spinning Black Holes, The Astrophysical Journal. 2007; 657 :383. astro-ph/0607145 - 61.
Zalamea I, Beloborodov AM. Neutrino heating near hyper-accreting black holes. Monthly Notices of the Royal Astronomical Society. 2011; 410 (2302):1003.0710 - 62.
Globus N, Levinson A. Loaded magnetohydrodynamic flows in Kerr spacetime. Physical Review D. 2013; 88 (084046):1310.0360 - 63.
Kawanaka N, Piran T, Krolik JH. Jet Luminosity from Neutrino-dominated Accretion Flows in Gamma-Ray Bursts. The Astrophysical Journal. 2013; 766 (31):1211.5110 - 64.
Lindner CC, Milosavljevíc M, Couch SM, Kumar P. Collapsar Accretion and the Gamma-Ray Burst X-Ray Light Curve. The Astrophysical Journal. 2010; 713 (2):800 - 65.
Just O et al. Neutron-star Merger Ejecta as Obstacles to Neutrino-powered Jets of Gamma-Ray Bursts, The Astrophysical Journal. 2016; 816 :L30. 1510.04288 - 66.
Fong W, Berger E, Margutti R, Zauderer BA. A Decade of Short-duration Gamma-Ray Burst Broadband Afterglows: Energetics, Circumburst Densities, and Jet Opening Angles. The Astrophysical Journal. 2015; 815 (102):1509.02922 - 67.
Levinson A, Globus N. Ultra-relativistic, Neutrino-driven Flows in Gamma-Ray Bursts: A Double Transonic Flow Solution in a Schwarzschild Spacetime. The Astrophysical Journal. 2013; 770 (159). 1303.4261 - 68.
Komissarov SS. Blandford-Znajek Mechanism versus Penrose Process. Journal of Korean Physical Society. 2009; 54 (2503):0804.1912 - 69.
Lee HK, Wijers RAMJ, Brown GE. The Blandford-Znajek process as a central engine for a gamma-ray burst. Physics Reports. 2000; 325 (83). astro-ph/9906213 - 70.
Wang DX, Xiao K, Lei WH. Evolution characteristics of the central black hole of a magnetized accretion disc. Monthly Notices of the Royal Astronomical Society. 2002; 335 (655). astro-ph/0209368 - 71.
Tchekhovskoy A, McKinney JC. Prograde and retrograde black holes: Whose jet is more powerful? Monthly Notices of the Royal Astronomical Society. 2012; 423 (L55):1201.4385 - 72.
Kumar P, Zhang B. The physics of gamma-ray bursts relativistic jets. Phys. Rep. 2015; 561 (1):1410.0679 - 73.
McKinney JC, Tchekhovskoy A, Blandford RD. General relativistic magnetohydrodynamic simulations of magnetically choked accretion flows around black holes. Monthly Notices of the Royal Astronomical Society. 2012; 423 (3083):1201.4163 - 74.
Bisnovatyi-Kogan GS, Ruzmaikin AA. The Accretion of Matter by a Collapsing Star in the Presence of a Magnetic Field. Astrophysics and Space Science. 1974; 28 :45 - 75.
Narayan R, Igumenshchev IV, Abramowicz MA. Magnetically Arrested Disk: An Energetically Efficient Accretion Flow. Publications of the Astronomical Society of Japan. 2003; 55 :L69. astro-ph/0305029 - 76.
Heyvaerts J, Norman C. The collimation of magnetized winds. The Astrophysical Journal. 1989; 347 :1055 - 77.
Begelman MC, Li Z-Y. Asymptotic domination of cold relativistic MHD winds by kinetic energy flux. The Astrophysical Journal. 1994; 426 :269 - 78.
Beskin VS, Kuznetsova IV, Rafikov RR. On the MHD effects on the force-free monopole outflow. Monthly Notices of the Royal Astronomical Society. 1998; 299 :341 - 79.
Tomimatsu A. Asymptotic collimation of magnetized winds far outside the light cylinder. Publications of the Astronomical Society of Japan. 1994; 46 :123 - 80.
Mizuta A, Aloy MA. Angular Energy Distribution of Collapsar-Jets. The Astrophysical Journal. 2009; 699 (1261):0812.4813 - 81.
Lazzati D, Morsony BJ, Begelman MC. Very High Efficiency Photospheric Emission in Long-Duration γ-Ray Bursts. The Astrophysical Journal. 2009; 700 (L47):0904.2779 - 82.
Bromberg O, Tchekhovskoy A. Relativistic MHD simulations of core-collapse GRB jets: 3D instabilities and magnetic dissipation. Monthly Notices of the Royal Astronomical Society. 2016; 456 (1739):1508.02721 - 83.
Bromberg O, Granot J, Lyubarsky Y, Piran T. The dynamics of a highly magnetized jet propagating inside a star. Monthly Notices of the Royal Astronomical Society. 2014; 443 (1532):1402.4142 - 84.
Globus N, Levinson A. The collimation of magnetic jets by disc winds. Monthly Notices of the Royal Astronomical Society. 2016; 461 (2605):1604.07408 - 85.
Granot J et al. Gamma-Ray Bursts as Sources of Strong Magnetic Fields. Space Science Reviews. 191. 1507; 471 (2015):08671 - 86.
Bromberg O, Granot J, Piran T. On the composition of GRBs’ Collapsar jets. Monthly Notices of the Royal Astronomical Society. 2015; 450 (1077):1407.0123 - 87.
Goodman J. Are gamma-ray bursts optically thick? The Astrophysical Journal. 1986; 308 :L47 - 88.
Hascöet R, Daigne F, Mochkovitch R. Prompt thermal emission in gamma-ray bursts. Astronomy and Astrophysics. 2013; 551 :A124. 1302.0235 - 89.
Thompson C. A Model of Gamma-Ray Bursts. Monthly Notices of the Royal Astronomical Society. 1994; 270 :480 - 90.
Giannios D, Spruit HC. Spectral and timing properties of a dissipative γ-ray burst photosphere. Astronomy and Astrophysics. 2007; 469 :1. astro-ph/0611385 - 91.
Rees MJ, Meszaros P. Unsteady outflow models for cosmological gamma-ray bursts. The Astrophysical Journal. 1994; 430 (L93). astro-ph/9404038 - 92.
Kobayashi S, Piran T, Sari R. Can Internal Shocks Produce the Variability in Gamma-Ray Bursts? The Astrophysical Journal. 1997; 490 (92). astro-ph/9705013 - 93.
Daigne F, Mochkovitch R. The expected thermal precursors of gamma-ray bursts in the internal shock model. Monthly Notices of the Royal Astronomical Society. 2002; 336 :1271. astro-ph/0207456 - 94.
Mimica P, Giannios D, Aloy MA. Deceleration of arbitrarily magnetized GRB ejecta: The complete evolution. Astronomy and Astrophysics. 2009; 494 (879):0810.2961 - 95.
Narayan R, Kumar P, Tchekhovskoy A. Constraints on cold magnetized shocks in gamma-ray bursts. Monthly Notices of the Royal Astronomical Society. 2011; 416 (2193):1105.0003 - 96.
Drenkhahn G, Spruit, HC. Efficient acceleration and radiation in Poynting flux powered GRB outflows. Astronomy and Astrophysics. 2002; 391 :1141. astro-ph/0202387 - 97.
Giannios D. Prompt GRB emission from gradual energy dissipation. Astronomy and Astrophysics. 2008; 480 :305. 0711.2632 - 98.
McKinney JC, Uzdensky DA. A reconnection switch to trigger gamma-ray burst jet dissipation. Monthly Notices of the Royal Astronomical Society. 2012; 419 (573):1011.1904 - 99.
Sapountzis K, Vlahakis N. Rarefaction acceleration in magnetized gamma-ray burst jets. Monthly Notices of the Royal Astronomical Society. 2013; 434 (1779):1407.4966 - 100.
Kagan D, Sironi L, Cerutti B, Giannios D. Relativistic Magnetic Reconnection in Pair Plasmas and Its Astrophysical Applications. Space Science Reviews. 2015; 191 (1-4):545 - 101.
Abbott, BP et al., Observation of Gravitational Waves from a Binary Black Hole Merger. Physical Review Letters. 2016; 116 (6). 061102, 1602.03837 - 102.
Spera M, Mapelli M, Bressan A. The mass spectrum of compact remnants from the PARSEC stellar evolution tracks. Monthly Notices of the Royal Astronomical Society. 2015; 451 (4086):1505.05201 - 103.
Janiuk A, Charzýnski S, Bejger M. Long gamma ray bursts from binary black holes. Astronomy and Astrophysics. 560, A25 (2013), 1310.4869 - 104.
Connaughton V et al. Fermi GBM Observations of LIGO Gravitational-wave Event GW150914, The Astrophysical Journal. 2016; 826 (L6): 1602.03920 - 105.
Connaughton V et al. On the Interpretation of the Fermi-GBM Transient Observed in Coincidence with LIGO Gravitational-wave Event GW150914, The Astrophysical Journal. 2018; 853 (L9):1801.02305 - 106.
Janiuk A, Bejger M, Charzýnski S, Sukova P. On the possible gamma-ray burst-gravitational wave association in GW150914, New A 51, 7 (2017), 1604.07132 - 107.
Loeb A. Electromagnetic Counterparts to Black Hole Mergers Detected by LIGO. The Astrophysical Journal. 2016; 819 (L21):1602.04735 - 108.
Perna, R, Lazzati D, Giacomazzo B. Short Gamma-Ray Bursts from the Merger of Two Black Holes. The Astrophysical Journal. 2016; 821 (L18):1602.05140 - 109.
Woosley SE. The Progenitor of GW150914. The Astrophysical Journal. 2016; 824 (L10):1603.00511 - 110.
Zhang B. Mergers of Charged Black Holes: Gravitational-wave Events, Short Gamma-Ray Bursts, and Fast Radio Bursts. The Astrophysical Journal. 2016; 827 (L31):1602.04542 - 111.
Abbott BP et al. Gravitational Waves and Gamma-Rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A. The Astrophysical Journal. 2017: 848 (L13):1710.05834 - 112.
Granot J, Guetta D, Gill R. Lessons from the Short GRB 170817A: The First Gravitational-wave Detection of a Binary Neutron Star Merger. The Astrophysical Journal. 2017; 850 (L24):1710.06407