Binary-driven Hypernovae Research Articles

Fitting the Crab Supernova with a Gamma-Ray Burst

Here, we reconsider the historical data, assuming a gamma-ray burst (GRB) as its source. A Supernova correlated with the GRB explains well the fading time observed by the ancient Chinese astronomers in the daytime and the nighttime, while the GRB power law explains the present X-rays and GeV emission of the Crab. On the grounds of a recent understanding of the first episode of binary-driven hypernova GRB (BDHN GRB) in terms of the collapse of a ten solar masses core, we propose the possible identification of the real Supernova event at an earlier time than Chinese chronicles. This work allows a new understanding of the significance of historical astronomical observations, including a fireball due to gamma-ray air shower observation and a plague of acute radiation syndrome, documented with several thousands of victims in the Eurasian area (Egypt, Iraq, and Syria).

Probing Electromagnetic Gravitational-wave Emission Coincidence in a Type I Binary-driven Hypernova Family of Long Gamma-Ray Bursts at Very High Redshift

The repointing time of the X-Ray Telescope (XRT) instrument on the Neil Gehrels Swift Observatory satellite has posed challenges in observing and studying the early X-ray emissions within ≈40 s after a gamma-ray burst (GRB) trigger. To address this issue, we adopt a novel approach that capitalizes on the cosmological time dilation in GRBs with redshifts ranging from 3 to 9. Applying this strategy to Swift/XRT data, we investigate the earliest X-ray emissions of 368 GRBs from the Swift catalog, including short and long GRBs. We compare the observed time delay between the GRB trigger and the initial Swift/XRT observation, measured in the GRB observer frame, and the corresponding cosmological rest-frame time delay (RTD). This technique is here used in the analysis of GRB 090423 at z = 8.233 (RTD ∼8.2 s), GRB 090429B at z ≈ 9.4 (RTD ∼10.1 s), and GRB 220101A at z = 4.61 (RTD ∼14.4 s). The cosmological time dilation enables us to observe the very early X-ray afterglow emission in these three GRBs. We thus validate the observation of the collapse of the carbon–oxygen core and the coeval newborn neutron star (νNS) formation triggering the GRB event in the binary-driven hypernova (BdHN) scenario. We also evidence the νNS spin-up due to supernova ejecta fallback and its subsequent slowing down due to the X-ray/optical/radio synchrotron afterglow emission. A brief gravitational-wave signal may separate the two stages owing to a fast-spinning νNS triaxial-to-axisymmetric transition. We also analyze the long GRB redshift distribution for the different BdHN types and infer that BdHNe II and III may originate the NS binary progenitors of short GRBs.

GRB-SN Association within the Binary-driven Hypernova Model

Observations of supernovae (SNe) Ic occurring after the prompt emission of long gamma-ray bursts (GRBs) are addressed within the binary-driven hypernova (BdHN) model where GRBs originate from a binary composed of a ∼10M ⊙ carbon–oxygen (CO) star and a neutron star (NS). The CO core collapse gives the trigger, leading to a hypernova with a fast-spinning newborn NS (νNS) at its center. The evolution depends strongly on the binary period, P bin. For P bin ∼ 5 min, BdHNe I occur with energies 1052–1054 erg. The accretion of SN ejecta onto the NS leads to its collapse, forming a black hole (BH) originating the MeV/GeV radiation. For P bin ∼ 10 min, BdHNe II occur with energies 1050–1052 erg and for P bin ∼ hours, BdHNe III occur with energies below 1050 erg. In BdHNe II and III, no BH is formed. The 1–1000 ms νNS originates, in all BdHNe, the X-ray-optical-radio afterglows by synchrotron emission. The hypernova follows an independent evolution, becoming an SN Ic, powered by nickel decay, observable after the GRB prompt emission. We report 24 SNe Ic associated with BdHNe. Their optical peak luminosity and time of occurrence are similar and independent of the associated GRBs. From previously identified 380 BdHN I comprising redshifts up to z = 8.2, we analyze four examples with their associated hypernovae. By multiwavelength extragalactic observations, we identify seven new episodes, theoretically explained, fortunately not yet detected in Galactic sources, opening new research areas. Refinement of population synthesis simulations is needed to map the progenitors of such short-lived binary systems inside our galaxy.

Neutron Star Binaries Produced by Binary-Driven Hypernovae, Their Mergers, and the Link between Long and Short GRBs

The binary-driven hypernova (BdHN) model explains long gamma-ray bursts (GRBs) associated with supernovae (SNe) Ic through physical episodes that occur in a binary composed of a carbon-oxygen (CO) star and a neutron star (NS) companion in close orbit. The CO core collapse triggers the cataclysmic event, originating the SN and a newborn NS (hereafter νNS) at its center. The νNS and the NS accrete SN matter. BdHNe are classified based on the NS companion fate and the GRB energetics, mainly determined by the orbital period. In BdHNe I, the orbital period is of a few minutes, so the accretion causes the NS to collapse into a Kerr black hole (BH), explaining GRBs of energies >1052 erg. BdHN II, with longer periods of tens of minutes, yields a more massive but stable NS, accounting for GRBs of 1050–1052 erg. BdHNe III have still longer orbital periods (e.g., hours), so the NS companion has a negligible role, which explains GRBs with a lower energy release of <1050 erg. BdHN I and II might remain bound after the SN, so they could form NS-BH and binary NS (BNS), respectively. In BdHN III, the SN likely disrupts the system. We perform numerical simulations of BdHN II to compute the characteristic parameters of the BNS left by them, their mergers, and the associated short GRBs. We obtain the mass of the central remnant, whether it is likely to be a massive NS or a BH, the conditions for disk formation and its mass, and the event’s energy release. The role of the NS nuclear equation of state is outlined.

Self-similarities and Power Laws in the Time-resolved Spectra of GRB 190114C, GRB 130427A, GRB 160509A, and GRB 160625B

Binary-driven hypernova (BdHN) models have been adopted to explain the observed properties of long gamma-ray bursts (GRBs). Here, we perform a comprehensive data analysis (temporal and spectral analysis, GeV emission, and afterglow) on GRB 130427A, GRB 160509A, and GRB 160625B. We identify three specific episodes characterized by different observational signatures and show that these episodes can be explained and predicted to occur within the framework of the BdHNe I model, as first observed in GRB 190114C and reported in an accompanying paper. Episode 1 includes the “SN-rise” with the characteristic cutoff power-law spectrum; Episode 2 is initiated by the moment of formation of the black hole, coincident with the onset of the GeV emission and the ultrarelativistic prompt emission phase, and is characterized by a cutoff power law and blackbody spectra; Episode 3 is the “cavity,” with its characteristic featureless spectrum.

GRB 171205A: Hypernova and Newborn Neutron Star

GRB 171205A is a low-luminosity, long-duration gamma-ray burst (GRB) associated with SN 2017iuk, a broad-line type Ic supernova (SN). It is consistent with having been formed in the core collapse of a widely separated binary, which we have called the binary-driven hypernova of type III. The core collapse of the CO star forms a newborn NS (νNS) and the SN explosion. Fallback accretion transfers mass and angular momentum to the νNS, here assumed to be born non-rotating. The accretion energy injected into the expanding stellar layers powers the prompt emission. The multiwavelength power-law afterglow is explained by the synchrotron radiation of electrons in the SN ejecta, powered by energy injected by the spinning νNS. We calculate the amount of mass and angular momentum gained by the νNS, as well as the νNS rotational evolution. The νNS spins up to a period of 47 ms, then releases its rotational energy powering the synchrotron emission of the afterglow. The paucity of the νNS spin explains the low-luminosity characteristic and that the optical emission of the SN from the nickel radioactive decay outshines the optical emission from the synchrotron radiation. From the νNS evolution, we infer that the SN explosion had to occur at most 7.36 h before the GRB trigger. Therefore, for the first time, the analysis of the GRB data leads to the time of occurrence of the CO core collapse leading to the SN explosion and the electromagnetic emission of the GRB event.

MeV, GeV and TeV Neutrinos from Binary-Driven Hypernovae

We analyze neutrino emission channels in energetic (≳1052 erg) long gamma-ray bursts within the binary-driven hypernova model. The binary-driven hypernova progenitor is a binary system composed of a carbon-oxygen star and a neutron star (NS) companion. The gravitational collapse leads to a type Ic supernova (SN) explosion and triggers an accretion process onto the NS. For orbital periods of a few minutes, the NS reaches the critical mass and forms a black hole (BH). Two physical situations produce MeV neutrinos. First, during the accretion, the NS surface emits neutrino–antineutrino pairs by thermal production. We calculate the properties of such a neutrino emission, including flavor evolution. Second, if the angular momentum of the SN ejecta is high enough, an accretion disk might form around the BH. The disk’s high density and temperature are ideal for MeV-neutrino production. We estimate the flavor evolution of electron and non-electron neutrinos and find that neutrino oscillation inside the disk leads to flavor equipartition. This effect reduces (compared to assuming frozen flavor content) the energy deposition rate of neutrino–antineutrino annihilation into electron–positron (e+e−) pairs in the BH vicinity. We then analyze the production of GeV-TeV neutrinos around the newborn black hole. The magnetic field surrounding the BH interacts with the BH gravitomagnetic field producing an electric field that leads to spontaneous e+e− pairs by vacuum breakdown. The e+e− plasma self-accelerates due to its internal pressure and engulfs protons during the expansion. The hadronic interaction of the protons in the expanding plasma with the ambient protons leads to neutrino emission via the decay chain of π-meson and μ-lepton, around and far from the black hole, along different directions. These neutrinos have energies in the GeV-TeV regime, and we calculate their spectrum and luminosity. We also outline the detection probability by some current and future neutrino detectors.

Evidence for the transition of a Jacobi ellipsoid into a Maclaurin spheroid in gamma-ray bursts

In the binary-driven hypernova (BdHN) scenario, long gamma-ray bursts (GRBs) originate in a cataclysmic event that occurs in a binary system composed of a carbon-oxygen (CO) star and a neutron star (NS) companion in close orbit. The collapse of the CO star generates at its center a newborn NS ($\nu$NS), and a supernova (SN) explosion. Matter from the ejecta is accreted both onto the $\nu$NS because of fallback and onto the NS companion, leading to the collapse of the latter into a black hole (BH). Each of the ingredients of the above system leads to observable emission episodes in a GRB. In particular, the $\nu$NS is expected to show up (hereafter $\nu$NS-rise) in the early GRB emission, nearly contemporary or superimposed to the ultrarelativistic prompt emission (UPE) phase, but with a different spectral signature. Following the $\nu$NS-rise, the $\nu$NS powers the afterglow emission by injecting energy into the expanding ejecta leading to synchrotron radiation. We here show that the $\nu$NS-rise and the subsequent afterglow emission in both systems, GRB 180720B and GRB 190114C, are powered by the release of rotational energy of a Maclaurin spheroid, starting from the bifurcation point to the Jacobi ellipsoid sequence. This implies that the $\nu$NS evolves from a triaxial Jacobi configuration, prior to the $\nu$NS-rise, into the axially symmetric Maclaurin configuration observed in the GRB. The triaxial $\nu$NS configuration is short-lived (less than a second) due to a copious emission of gravitational waves, before the GRB emission, and it could be in principle detected for sources located at distances closer than $100$ Mpc. This appears to be a specific process of emission of gravitational waves in the BdHN I powering long GRBs.

First minutes of a binary-driven hypernova

We simulate the first minutes of the evolution of a binary-driven hypernova (BdHN) event, with a special focus on the associated accretion processes of supernova (SN) ejecta onto the newborn neutron star ($\nu$NS) and the NS companion. We calculate the rotational evolution of the $\nu$NS and the NS under the torques exerted by the accreted matter and the magnetic field. We take into account general relativistic effects and use realistic hypercritical accretion rates obtained from three-dimensional smoothed-particle-hydrodynamics (SPH) numerical simulations of the BdHN for a variety of orbital periods. We show that the rotation power of the $\nu$NS has a unique double-peak structure while that of the NS has a single peak. These peaks are of comparable intensity and can occur very close in time or even simultaneously depending on the orbital period and the initial angular momentum of the stars. We outline the consequences of the above features in the early emission and their consequent observation in long gamma-ray bursts (GRBs).

The structure of the ultrarelativistic prompt emission phase and the properties of the black hole in GRB 180720B

In analogy with GRB 190114C, we here analyze the ultrarelativistic prompt emission (UPE) of GRB 180720B observed in the rest-frame time interval t_{mathrm{rf}}=4.84–10.89 s by Fermi-GBM. We reveal the UPE hierarchical structure from the time-resolved spectral analysis performed in time sub-intervals: the spectrum in each shorter time interval is always fitted by a composite blackbody plus cutoff power-law model. We explain this structure with the inner engine of binary-driven hypernova (BdHN) model operating in a quantum electrodynamics (QED) regime. In this regime, the electric field induced by the gravitomagnetic interaction of the newborn Kerr BH with the surrounding magnetic field is overcritical, i.e., |mathbf{E}|ge E_c, where E_c=m_e^2 c^3/(ehbar ). The overcritical field polarizes the vacuum leading to an e^+~e^- pair plasma that loads baryons from the surroundings during its expansion. We calculate the dynamics of the self-acceleration of the pair-electromagnetic-baryon (PEMB) pulses to their point of transparency. We characterize the quantum vacuum polarization process in the sequences of decreasing time bins of the UPE by determining the radiation timescale, Lorentz factors, and transparency radius of the PEMB pulses. We also estimate the strength of the surrounding magnetic field sim 10^{14} G, and obtain a lower limit to the BH mass, M=2.4~M_odot , and correspondingly an upper limit to the spin, alpha = 0.6, from the conditions that the UPE is powered by the Kerr BH extractable energy and its mass is bound from below by the NS critical mass.

GRB 190829A—A Showcase of Binary Late Evolution

GRB 190829A is the fourth-closest gamma-ray burst to date (z = 0.0785). Owing to its wide range of radio, optical, X-ray, and very-high-energy observations by HESS, it has become an essential new source that has been examined by various models with complementary approaches. Here, we show in GRB 190829A that the double prompt pulses and the three multiwavelength afterglows are consistent with the type II binary-driven hypernova model. The progenitor is a binary composed of a carbon–oxygen (CO) star and a neutron star (NS) companion. The gravitational collapse of the iron core of the CO star produces a supernova (SN) explosion and leaves behind a new NS (νNS) at its center. The accretion of the SN ejecta onto the NS companion and onto the νNS via matter fallback spins up the NSs and produces the double-peak prompt emission. The synchrotron emission from the expanding SN ejecta, with energy injection from the rapidly spinning νNS and its subsequent spindown, leads to the afterglow in the radio, optical, and X-ray bands. We model the sequence of physical and related radiation processes in BdHNe, and focus on individuating the binary properties that play the relevant roles.

A brief review of binary-driven hypernova

Binary-driven hypernova (BdHN) models long gamma-ray burst (GRB) as occurring in the binary systems involving a carbon–oxygen core (CO[Formula: see text]) and a companion neutron star (NS) or a black hole (BH). This model, first proposed in 2012, succeeds and improves upon the fireshell model and the induced gravitational collapse (IGC) paradigm. After nearly a decade of development, the BdHN model has reached a nearly complete structure, giving explanation to all the observables of long bursts into its theoretical framework, and has given a refined classification of long GRB according to the original properties of the progenitors. In this paper, we present a summary of the BdHN model and the physical processes at work in each of the envisaged Episodes during its occurrence and lifetime, duly contextualized in the framework of GRB observations.

The morphology of the X-ray afterglows and of the jetted GeV emission in long GRBs

ABSTRACT We recall evidence that long gamma-ray bursts (GRBs) have binary progenitors and give new examples. Binary-driven hypernovae (BdHNe) consist of a carbon–oxygen core (COcore) and a neutron star (NS) companion. For binary periods ∼5 min, the COcore collapse originates the subclass BdHN I characterized by (1) an outstanding supernova (SN; the ‘SN-rise’); (2) a black hole (BH), born from the NS collapse by SN matter accretion, leading to a GeV emission with luminosity $L_{\rm GeV} = A_{\rm GeV}\, t^{-\alpha _{\rm GeV}}$, observed only in some cases; and (3) a new NS (νNS), born from the SN, originating from the X-ray afterglow with $L_\mathrm{ X} = A_{\rm X}\, t^{-\alpha _{\rm X}}$, observed in all BdHN I. We record 378 sources and present for four prototype GRBs 130427A, 160509A, 180720B, and 190114C: (1) spectra, luminosities, SN-rise duration; (2) AX, αX = 1.48 ± 0.32, and (3) the νNS spin time evolution. We infer (i) AGeV, αGeV = 1.19 ± 0.04 and (ii) the BdHN I morphology from time-resolved spectral analysis, three-dimensional simulations, and the GeV emission presence/absence in 54 sources within the Fermi-Large Area Telescope boresight angle. For 25 sources, we give the integrated and time-varying GeV emission, 29 sources have no GeV emission detected and show X/gamma-ray flares previously inferred as observed along the binary plane. The 25/54 ratio implies the GeV radiation is emitted within a cone of half-opening angle ≈60° from the normal to the orbital plane. We deduce BH masses of 2.3–8.9 M⊙ and spin of 0.27–0.87 by explaining the GeV emission from the BH rotational energy extraction, while their time evolution validates the BH mass–energy formula.

Neutrino Oscillations in Neutrino-Dominated Accretion Around Rotating Black Holes

In the binary-driven hypernova model of long gamma-ray bursts, a carbon–oxygen star explodes as a supernova in the presence of a neutron star binary companion in close orbit. Hypercritical (i.e., highly super-Eddington) accretion of the ejecta matter onto the neutron star sets in, making it reach the critical mass with consequent formation of a Kerr black hole. We have recently shown that, during the accretion process onto the neutron star, fast neutrino flavor oscillations occur. Numerical simulations of the above system show that a part of the ejecta stays bound to the newborn Kerr black hole, leading to a new process of hypercritical accretion. We address herein, also for this phase of the binary-driven hypernova, the occurrence of neutrino flavor oscillations given the extreme conditions of high density (up to 1012 g cm−3) and temperatures (up to tens of MeV) inside this disk. We estimate the behavior of the electronic and non-electronic neutrino content within the two-flavor formalism (νeνx) under the action of neutrino collective effects by neutrino self-interactions. We find that in the case of inverted mass hierarchy, neutrino oscillations inside the disk have frequencies between ∼(105–109) s−1, leading the disk to achieve flavor equipartition. This implies that the energy deposition rate by neutrino annihilation (ν+ν¯→e−+e+) in the vicinity of the Kerr black hole is smaller than previous estimates in the literature not accounting for flavor oscillations inside the disk. The exact value of the reduction factor depends on the νe and νx optical depths but it can be as high as ∼5. The results of this work are a first step toward the analysis of neutrino oscillations in a novel astrophysical context, and as such, deserve further attention.

Magnetic Fields and Afterglows of BdHNe: Inferences from GRB 130427A, GRB 160509A, GRB 160625B, GRB 180728A, and GRB 190114C

Abstract GRB 190114C is the first binary-driven hypernova (BdHN) fully observed from initial supernova (SN) appearance to the final emergence of the optical SN signal. It offers an unprecedented testing ground for the BdHN theory, which is here determined and further extended to additional gamma-ray bursts (GRBs). BdHNe comprise two subclasses of long GRBs, with progenitors a binary system composed of a carbon–oxygen star (COcore) and a neutron star (NS) companion. The COcore explodes as an SN, leaving at its center a newborn NS (νNS). The SN ejecta hypercritically accretes on both the νNS and the NS companion. BdHNe I are very tight binaries, where the accretion leads the companion NS to gravitationally collapse into a black hole (BH). In BdHN II, the accretion rate onto the NS is lower, so there is no BH formation. We observe the same afterglow structure for GRB 190114C and other selected examples of BdHNe I (GRB 130427A, GRB 160509A, GRB 160625B) and for BdHN II (GRB 180728A). In all cases, the afterglows are explained via the synchrotron emission powered by the νNS, and their magnetic field structures and their spin are determined. For BdHNe I, we discuss the properties of the magnetic field embedding the newborn BH, which was inherited from the collapsed NS and amplified during the gravitational collapse process, and surrounded by the SN ejecta.

On the GeV Emission of the Type I BdHN GRB 130427A

Abstract We propose that the inner engine of a type I binary-driven hypernova (BdHN) is composed of Kerr black hole (BH) in a non-stationary state, embedded in a uniform magnetic field B 0 aligned with the BH rotation axis and surrounded by an ionized plasma of extremely low density of 10−14 g cm−3. Using GRB 130427A as a prototype, we show that this inner engine acts in a sequence of elementary impulses. Electrons accelerate to ultrarelativistic energy near the BH horizon, propagating along the polar axis, θ = 0, where they can reach energies of ∼1018 eV, partially contributing to ultrahigh-energy cosmic rays. When propagating with through the magnetic field B 0, they produce GeV and TeV radiation through synchroton emission. The mass of BH, M = 2.31M ⊙, its spin, α = 0.47, and the value of magnetic field B 0 = 3.48 × 1010 G, are determined self consistently to fulfill the energetic and the transparency requirement. The repetition time of each elementary impulse of energy erg is ∼10−14 s at the beginning of the process, then slowly increases with time evolution. In principle, this “inner engine” can operate in a gamma-ray burst (GRB) for thousands of years. By scaling the BH mass and the magnetic field, the same inner engine can describe active galactic nuclei.

On the Role of a Cavity in the Hypernova Ejecta of GRB 190114C

Abstract Within the binary-driven hypernova I (BdHN I) scenario, the gamma-ray burst GRB190114C originates in a binary system composed of a massive carbon–oxygen core (COcore), and a binary neutron star (NS) companion. As the COcore undergoes a supernova explosion with the creation of a new neutron star (νNS), hypercritical accretion occurs on the companion binary neutron star until it exceeds the critical mass for gravitational collapse. The formation of a black hole (BH) captures 1057 baryons by enclosing them within its horizon, and thus a cavity of approximately 1011 cm is formed around it with initial density 10−7 g cm−3. A further depletion of baryons in the cavity originates from the expansion of the electron-positron-photon (e + e − γ) plasma formed at the collapse, reaching a density of 10−14 g cm−3 by the end of the interaction. It is demonstrated here using an analytical model complemented by a hydrodynamical numerical simulation that part of the e + e − γ plasma is reflected off the walls of the cavity. The consequent outflow and its observed properties are shown to coincide with the featureless emission occurring in a time interval of duration t rf, measured in the rest frame of the source, between 11 and 20 s of the GBM observation. Moreover, similar features of the GRB light curve were previously observed in GRB 090926A and GRB 130427A, all belonging to the BdHN I class. This interpretation supports the general conceptual framework presented in R. Ruffini et al. and guarantees that a low baryon density is reached in the cavity, a necessary condition for the operation of the “inner engine” of the GRB presented in an accompanying article.

Induced Gravitational Collapse, Binary-Driven Hypernovae, Long Gramma-ray Bursts and Their Connection with Short Gamma-ray Bursts

There is increasing observational evidence that short and long Gamma-ray bursts (GRBs) originate in different subclasses, each one with specific energy release, spectra, duration, etc, and all of them with binary progenitors. The binary components involve carbon-oxygen cores (CO core ), neutron stars (NSs), black holes (BHs), and white dwarfs (WDs). We review here the salient features of the specific class of binary-driven hypernovae (BdHNe) within the induced gravitational collapse (IGC) scenario for the explanation of the long GRBs. The progenitor is a CO core -NS binary. The supernova (SN) explosion of the CO core , producing at its center a new NS ( ν NS), triggers onto the NS companion a hypercritical, i.e., highly super-Eddington accretion process, accompanied by a copious emission of neutrinos. By accretion the NS can become either a more massive NS or reach the critical mass for gravitational collapse with consequent formation of a BH. We summarize the results on this topic from the first analytic estimates in 2012 all the way up to the most recent three-dimensional (3D) smoothed-particle-hydrodynamics (SPH) numerical simulations in 2018. Thanks to these results it is by now clear that long GRBs are richer and more complex systems than thought before. The SN explosion and its hypercritical accretion onto the NS explain the X-ray precursor. The feedback of the NS accretion, the NS collapse and the BH formation produce asymmetries in the SN ejecta, implying the necessity of a 3D analysis for GRBs. The newborn BH, the surrounding matter and the magnetic field inherited from the NS, comprises the inner engine from which the GRB electron-positron ( e + e − ) plasma and the high-energy emission are initiated. The impact of the e + e − on the asymmetric ejecta transforms the SN into a hypernova (HN). The dynamics of the plasma in the asymmetric ejecta leads to signatures depending on the viewing angle. This explains the ultrarelativistic prompt emission in the MeV domain and the mildly-relativistic flares in the early afterglow in the X-ray domain. The feedback of the ν NS pulsar-like emission on the HN explains the X-ray late afterglow and its power-law regime. All of the above is in contrast with a simple GRB model attempting to explain the entire GRB with the kinetic energy of an ultrarelativistic jet extending through all of the above GRB phases, as traditionally proposed in the “collapsar-fireball” model. In addition, BdHNe in their different flavors lead to ν NS-NS or ν NS-BH binaries. The gravitational wave emission drives these binaries to merge producing short GRBs. It is thus established a previously unthought interconnection between long and short GRBs and their occurrence rates. This needs to be accounted for in the cosmological evolution of binaries within population synthesis models for the formation of compact-object binaries.

Two Predictions of Supernova: GRB 130427A/SN 2013cq and GRB 180728A/SN 2018fip

Abstract On 2018 July 28, GRB 180728A triggered Swift satellites and, soon after the determination of the redshift, we identified this source as a type II binary-driven hypernova (BdHN II) in our model. Consequently, we predicted the appearance time of its associated supernova (SN), which was later confirmed as SN 2018fip. A BdHN II originates in a binary composed of a carbon–oxygen core (COcore) undergoing SN, and the SN ejecta hypercritically accrete onto a companion neutron star (NS). From the time of the SN shock breakout to the time when the hypercritical accretion starts, we infer the binary separation ≃3 × 1010 cm. The accretion explains the prompt emission of isotropic energy ≃3 × 1051 erg, lasting ∼10 s, and the accompanying observed blackbody emission from a thermal convective instability bubble. The new neutron star (νNS) originating from the SN powers the late afterglow from which a νNS initial spin of 2.5 ms is inferred. We compare GRB 180728A with GRB 130427A, a type I binary-driven hypernova (BdHN I) with isotropic energy >1054 erg. For GRB 130427A we have inferred an initially closer binary separation of ≃1010 cm, implying a higher accretion rate leading to the collapse of the NS companion with consequent black hole formation, and a faster, 1 ms spinning νNS. In both cases, the optical spectra of the SNe are similar, and not correlated to the energy of the gamma-ray burst. We present three-dimensional smoothed-particle-hydrodynamic simulations and visualizations of the BdHNe I and II.

SPH Simulations of the Induced Gravitational Collapse Scenario of Long Gamma-Ray Bursts Associated with Supernovae

Abstract We present the first three-dimensional smoothed particle hydrodynamics simulations of the induced gravitational collapse scenario of long-duration gamma-ray bursts (GRBs) associated with supernovae (SNe). We simulate the SN explosion of a carbon–oxygen core (COcore) forming a binary system with a neutron star (NS) companion. We follow the evolution of the SN ejecta, including their morphological structure, subject to the gravitational field of both the new NS (νNS) formed at the center of the SN and the one of the NS companion. We compute the accretion rate of the SN ejecta onto the NS companion, as well as onto the νNS from SN matter fallback. We determine the fate of the binary system for a wide parameter space including different COcore and NS companion masses, orbital periods, and SN explosion geometry and energies. We identify, for selected NS nuclear equations of state, the binary parameters leading the NS companion, by hypercritical accretion, either to the mass-shedding limit or to the secular axisymmetric instability for gravitational collapse to a black hole (BH), or to a more massive, fast-rotating, stable NS. We also assess whether the binary remains gravitationally bound after the SN explosion, hence exploring the space of binary and SN explosion parameters leading to νNS–NS and νNS–BH binaries. The consequences of our results for the modeling of long GRBs, i.e., X-ray flashes and binary-driven hypernovae, are discussed.