arXiv subjects

Y. Aimuratov

Publications and source records attributed to Y. Aimuratov.

14 recordsLinked to original sources

arXiv2026

GRB 220101A: a most energetic $10^{54}$ erg long GRB triggered by two supernovae 3.5 seconds apart

GRB 220101A is a long GRB, with a total energy exceeding $10^{54}$ erg with a redshift $z = 4.61$ and one of the largest ever high-quality multi-wavelength observational coverage, from a large number of space-based and ground-based telescopes. We interpret this source in a doubly Binary driven peta nova (BdP-N) model. The progenitor is composed of a massive CO core of $\sim 10\,M_\odot$, highly magnetized with $B \sim 10^{6}$ G, associated to a neutron star (NS) and a white dwarf (WD) with orbital periods from minutes to hours. The large GRB luminosity is explained by a sequence of 7 episodes: episode 1 is triggered by a new kind of pair supernova (HB) which originates from the collapse of the strongly magnetized CO core. Accretion of the HB supernova ejecta (the ejecta) onto the white dwarf companion triggers after 3.5 sec the episode 2: the second supernova emitting neutrinos and creating a new neutron star ($ν$NS). The ejecta, interacting with the magnetosphere of the binary NS companion originate the episode 3: the Ultra relativistic Prompt Emission (UPE) emission by far the most energetic episode of this GRB, with the formation of a powerful jet normal to the plane of the GRB. Following the UPE energy loss, the accretion of the ejecta on the NS companion leads to the episode 4: the formation of a black hole (BH) of $2.3 \ M_\odot$ leading to the observed GeV afterglow emission. Further accretion of the ejecta spin up the $ν$NS to a period of $1.3$ ms which gives origin to the episode 5: the birth of a pulsar. The interaction of this milli-second pulsar with the remnants lead to the Episode 6: the synchrotron emission observed in the X-ray, optical and radio, The episode 7 is a 56.7 ms pulsar, as observed $10^{10}$ s after the first burst in the crab nebula.

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arXiv2025

Selected topics on: 1) proposal of interpreting the Crab supernova with a GRB 2) progress in identifying the seven GRBs episodes 3) the role of Sagittarius A in identifying the dark matter component (the X fermion)

As the fiftieth anniversary of our common effort in the field of relativistic astrophysics is approaching, we offer a new look to some of our acquired knowledge in a more complete view, which evidence previous unnoticed connections. They are gaining due prominence in reaching a more complete picture evidencing the main results. We outline the history of GRB observations along with a summary of the contributions made by our group to develop the BdHN interpreting model. We show the seven Episodes characterizing the most powerful BdHNe I occurred to date: GRB 190114C and GRB 220101A. New inferences for the explanation of the highest energy radiation in the TeV are presented.

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arXiv2023

GRB-SN Association within the Binary-Driven Hypernova Model

The 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 $\sim10M_\odot$ 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 ($ν$NS) at its center. The evolution depends strongly on the binary period, $P_{\rm bin}$. For $P_{\rm bin}\sim5$min, BdHNe I occur with energies $10^{52}$--$10^{54}$erg. The accretion of SN ejecta onto the NS leads to its collapse, forming a black hole (BH) originating the MeV/GeV radiation. For $P_{\rm bin}\sim 10$min, BdHNe II occur with energies $10^{50}$--$10^{52}$erg and for $P_{\rm bin}\sim$hours, BdHN III occurs with energies below $10^{50}$erg. {In BdHNe II and III,} no BH is formed. The $1$--$1000$ms $ν$NS 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.

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arXiv2022

GRB 190829A -- A Showcase of Binary Late Evolution

GRB 190829A is the fourth closest gamma-ray burst (GRB) to date ($z=0.0785$). Owing to its wide range of radio, optical, X-ray, and the very-high-energy (VHE) observations by H.E.S.S., it has become an essential new source examined by various models with complementary approaches. We here show in GRB 190829A the double-prompt pulses and the three-multiwavelength afterglows are consistent with the type II binary-driven hypernova (BdHN II) 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 neutron star ($ν$NS) at its center. The accretion of the SN ejecta onto the NS companion and onto the $ν$NS via matter fallback spins up the NSs and produces the double-peak prompt emission. The synchrotron emission from the expanding SN ejecta with the energy injection from the rapidly spinning $ν$NS and its subsequently spin-down leads to the afterglow in the radio, optical, and X-ray. We model the sequence of physical and related radiation processes in BdHNe and focus on individuating the binary properties that play the relevant roles.

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arXiv2021

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

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 (CO$_{\rm core}$) and a neutron star (NS) companion. For binary periods $\sim 5$ min, the CO$_{\rm core}$ collapse originates the subclass BdHN I characterized by: 1) an energetic supernova (the "SN-rise"); 2) a black hole (BH), born from the NS collapse by SN matter accretion, leading to a GeV emission with luminosity $L_{\rm GeV} = A_{\rm GeV}\,t^{-α_{\rm GeV}}$, observed only in some cases; 3) a new NS ($ν$NS), born from the SN, originating the X-ray afterglow with $L_X = A_{\rm X}\,t^{-α_{\rm X}}$, observed in all BdHN I. We record $378$ sources and present for four prototypes GRBs 130427A, 160509A, 180720B and 190114C: 1) spectra, luminosities, SN-rise duration; 2) $A_X$, $α_X=1.48\pm 0.32$, and 3) the $ν$NS spin time-evolution. We infer a) $A_{\rm GeV}$, $α_{\rm GeV}=1.19 \pm 0.04$; b) the BdHN I morphology from time-resolved spectral analysis, three-dimensional simulations, and the GeV emission presence/absence in $54$ sources within the Fermi-LAT 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 $\approx 60^{\circ}$ from the normal to the orbital plane. We deduce BH masses $2.3$-$8.9~M_\odot$ and spin $0.27$-$0.87$ by explaining the GeV emission from the BH energy extraction, while their time evolution validates the BH mass-energy formula.

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arXiv2020

On the role of the Kerr-Newman black hole in the GeV emission of long gamma-ray bursts

X-ray Flashes (XRFs), binary-driven hypernovae (BdHNe) are long GRB subclasses with progenitor a CO$_{\rm core}$, undergoing a supernova (SN) explosion and hypercritically accreting in a tight binary system onto a companion neutron star (NS) or black hole (BH). In XRFs the NS does not reach by accretion the critical mass and no BH is formed. In BdHNe I, with shorter binary periods, the NS gravitationally collapses and leads to a new born BH. In BdHNe II the accretion on an already formed BH leads to a more massive BH. We assume that the GeV emission observed by \textit{Fermi}-LAT originates from the rotational energy of the BH. Consequently, we verify that, as expected, in XRFs no GeV emission is observed. In $16$ BdHNe I and $5$ BdHNe II, within the boresight angle of LAT, the integrated GeV emission allows to estimate the initial mass and spin of the BH. In the remaining $27$ sources in the plane of the binary system no GeV emission occurs, hampered by the presence of the HN ejecta. From the ratio, $21/48$, we infer a new asymmetric morphology for the BdHNe reminiscent of the one observed in active galactic nuclei (AGN): the GeV emission occurs within a cone of half-opening angle $\approx 60^{\circ}$ from the normal to the orbital plane of the binary progenitor. The transparency condition requires a Lorentz factor $Γ\sim 1500$ on the source of GeV emission. The GeV luminosity in the rest-frame of the source follows a universal power-law with index of $-1.20 \pm 0.04$, allowing to estimate the spin-down rate of the BH

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arXiv2018

On the Short GRB GeV emission from a Kerr Black hole

It has recently become clear that in both short and long gamma-ray bursts (GRBs) it coexists a sequence of different events, each characterized by specific physical processes and corresponding values of the Lorentz gamma factors. The ultra-relativistic prompt emission (UPE) phase, with Lorentz factor $Γ\leq10^4$, is followed by a mildly relativistic plateau-afterglow phase with $Γ\lesssim2$. The GeV radiation, with $Γ\lesssim50$, coexists with the above two phases. It is shown that: a) the GeV radiation originates at the onset of the formation of a black hole (BH), b) its luminosity follows specific power-law dependence when measured in the rest frame of the source with a decay index $γ=-1.29\pm0.06$ in the case of the short GRBs, and $γ=-1.20\pm0.04$ in the case of the long GRBs, c) these energetics requirements are used to derive the mass and spin of the BH originating this extended GeV emission. We present these conceptual results for the case of short GRBs in this article and give the extended analysis for long GRBs in a companion article. A direct astrophysical application of these results is that the merger of binary neutron stars leading to BH formation emits GeV radiation: the GeV emission is a necessary and sufficient condition to indicate the creation of a BH in S-GRBs.

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arXiv2018

On the rate and on the gravitational wave emission of short and long GRBs

On the ground of the large number of gamma-ray bursts (GRBs) detected with cosmological redshift, we classified GRBs in seven subclasses, all with binary progenitors originating gravitational waves (GWs). Each binary is composed by combinations of carbon-oxygen cores (CO$_{\rm core}$), neutron stars (NSs), black holes (BHs) and white dwarfs (WDs). The long bursts, traditionally assumed to originate from a BH with an ultra-relativistic jetted emission, not emitting GWs, have been subclassified as (I) X-ray flashes (XRFs), (II) binary-driven hypernovae (BdHNe), and (III) BH-supernovae (BH-SNe). They are framed within the induced gravitational collapse (IGC) paradigm with progenitor a CO$_{\rm core}$-NS/BH binary. The supernova (SN) explosion of the CO$_{\rm core}$ triggers an accretion process onto the NS/BH. If the accretion does not lead the NS to its critical mass, an XRF occurs, while when the BH is present or formed by accretion, a BdHN occurs. When the binaries are not disrupted, XRFs lead to NS-NS and BdHNe lead to NS-BH. The short bursts, originating in NS-NS, are subclassified as (IV) short gamma-ray flashes (S-GRFs) and (V) short GRBs (S-GRBs), the latter when a BH is formed. There are (VI) ultra-short GRBs (U-GRBs) and (VII) gamma-ray flashes (GRFs), respectively formed in NS-BH and NS-WD. We use the occurrence rate and GW emission of these subclasses to assess their detectability by Advanced LIGO-Virgo, eLISA, and resonant bars. We discuss the consequences of our results in view of the announcement of the LIGO-Virgo Collaboration of the source GW 170817 as being originated by a NS-NS.

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arXiv2018

Revisiting the Statistics of X-ray Flares in Gamma-ray Bursts

The statistics of X-ray flares in the afterglow of gamma-ray bursts (GRBs) have been studied extensively without considering the possible different origins of each flare. By satisfying six observational criteria, we find a sample composed of $16$ long GRBs observed by \textit{Swift} satellite may share a same origin. By applying the Markov chain Monte Carlo iteration and the machine learning algorithms (locally weighted regression and Gaussian process regression), impressively, the flares in these GRBs show strong correlations with the energy released in the prompt emission. These correlations were never discovered in previous papers, and they could not be well explained by previous models. These correlations imply that the prompt emission and the X-ray flare are not independent, they may be originated following a same sequence. The new THESUS satellite will provide us a larger sample and more detailed spectra to refine the results we obtained in this article.

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arXiv2017

Early X-ray Flares in GRBs

We analyze the early X-ray flares in the GRB "flare-plateau-afterglow" (FPA) phase observed by Swift-XRT. The FPA occurs only in one of the seven GRB subclasses: the binary-driven hypernovae (BdHNe). This subclass consists of long GRBs with a carbon-oxygen core and a neutron star (NS) binary companion as progenitors. The hypercritical accretion of the supernova (SN) ejecta onto the NS can lead to the gravitational collapse of the NS into a black hole. Consequently, one can observe a GRB emission with isotropic energy $E_{iso}\gtrsim10^{52}$~erg, as well as the associated GeV emission and the FPA phase. Previous work had shown that gamma-ray spikes in the prompt emission occur at $\sim 10^{15}$--$10^{17}$~cm with Lorentz gamma factor $Γ\sim10^{2}$--$10^{3}$. Using a novel data analysis we show that the time of occurrence, duration, luminosity and total energy of the X-ray flares correlate with $E_{iso}$. A crucial feature is the observation of thermal emission in the X-ray flares that we show occurs at radii $\sim10^{12}$~cm with $Γ\lesssim 4$. These model independent observations cannot be explained by the "fireball" model, which postulates synchrotron and inverse Compton radiation from a single ultra relativistic jetted emission extending from the prompt to the late afterglow and GeV emission phases. We show that in BdHNe a collision between the GRB and the SN ejecta occurs at $\simeq10^{10}$~cm reaching transparency at $\sim10^{12}$~cm with $Γ\lesssim4$. The agreement between the thermal emission observations and these theoretically derived values validates our model and opens the possibility of testing each BdHN episode with the corresponding Lorentz gamma factor.

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arXiv2017

GRB 081024B and GRB 140402A: two additional short GRBs from binary neutron star mergers

Theoretical and observational evidences have been recently gained for a two-fold classification of short bursts: 1) short gamma-ray flashes (S-GRFs), with isotropic energy $E_{iso}<10^{52}$~erg and no BH formation, and 2) the authentic short gamma-ray bursts (S-GRBs), with isotropic energy $E_{iso}>10^{52}$~erg evidencing a BH formation in the binary neutron star merging process. The signature for the BH formation consists in the on-set of the high energy ($0.1$--$100$~GeV) emission, coeval to the prompt emission, in all S-GRBs. No GeV emission is expected nor observed in the S-GRFs. In this paper we present two additional S-GRBs, GRB 081024B and GRB 140402A, following the already identified S-GRBs, i.e., GRB 090227B, GRB 090510 and GRB 140619B. We also return on the absence of the GeV emission of the S-GRB 090227B, at an angle of $71^{\rm{o}}$ from the \textit{Fermi}-LAT boresight. All the correctly identified S-GRBs correlate to the high energy emission, implying no significant presence of beaming in the GeV emission. The existence of a common power-law behavior in the GeV luminosities, following the BH formation, when measured in the source rest-frame, points to a commonality in the mass and spin of the newly-formed BH in all S-GRBs.

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arXiv2016

On the universal late X-ray emission of binary-driven hypernovae and its possible collimation

It has previously been discovered that there is a universal power law behavior exhibited by the late X-ray emission (LXRE) of a "golden sample" (GS) of six long energetic GRBs, when observed in the rest-frame of the source. This remarkable feature, independent of the different isotropic energy (E_iso) of each GRB, has been used to estimate the cosmological redshift of some long GRBs. This analysis is extended here to a new class of 161 long GRBs, all with E_iso > 10^52 erg. These GRBs are indicated as binary-driven hypernovae (BdHNe) in view of their progenitors: a tight binary system composed of a carbon-oxygen core (CO_core) and a neutron star undergoing an induced gravitational collapse (IGC) to a black hole triggered by the CO_core explosion as a supernova (SN). We confirm the universal behavior of the LXRE for the "enlarged sample" (ES) of 161 BdHNe observed up to the end of 2015, assuming a double-cone emitting region. We obtain a distribution of half-opening angles peaking at 17.62 degrees, with a mean value of 30.05 degrees, and a standard deviation of 19.65 degrees. This, in turn, leads to the possible establishment of a new cosmological candle. Within the IGC model, such universal LXRE behavior is only indirectly related to the GRB and originates from the SN ejecta, of a standard constant mass, being shocked by the GRB emission. The fulfillment of the universal relation in the LXRE and its independence of the prompt emission, further confirmed in this article, establishes a crucial test for any viable GRB model.

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arXiv2016

On the classification of GRBs and their occurrence rates

There is mounting evidence for the binary nature of the progenitors of gamma-ray bursts (GRBs). For a long GRB, the induced gravitational collapse (IGC) paradigm proposes as progenitor, or "in-state", a tight binary system composed of a carbon-oxygen core (CO$_{core}$) undergoing a supernova (SN) explosion which triggers hypercritical accretion onto a neutron star (NS) companion. For a short GRB, a NS-NS merger is traditionally adopted as the progenitor. We divide long and short GRBs into two sub-classes, depending on whether or not a black hole (BH) is formed in the merger or in the hypercritical accretion process exceeding the NS critical mass. For long bursts, when no BH is formed we have the sub-class of X-ray flashes (XRFs), with isotropic energy $E_{iso}\lesssim10^{52}$ erg and rest-frame spectral peak energy $E_{p,i}\lesssim200$ keV. When a BH is formed we have the sub-class of binary-driven hypernovae (BdHNe), with $E_{iso}\gtrsim10^{52}$ erg and $E_{p,i}\gtrsim200$ keV. In analogy, short bursts are similarly divided into two sub-classes. When no BH is formed, short gamma-ray flashes (S-GRFs) occur, with $E_{iso}\lesssim10^{52}$ erg and $E_{p,i}\lesssim2$ MeV. When a BH is formed, the authentic short GRBs (S-GRBs) occur, with $E_{iso}\gtrsim10^{52}$ erg and $E_{p,i}\gtrsim2$ MeV. We give examples and observational signatures of these four sub-classes and their rate of occurrence. From their respective rates it is possible that "in-states" of S-GRFs and S-GRBs originate from the "out-states" of XRFs. We indicate two additional progenitor systems: white dwarf-NS and BH-NS. These systems have hybrid features between long and short bursts. In the case of S-GRBs and BdHNe evidence is given of the coincidence of the onset of the high energy GeV emission with the birth of a Kerr BH.

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arXiv2016

GRB 090510: a genuine short-GRB from a binary neutron star coalescing into a Kerr-Newman black hole

In a new classification of merging binary neutron stars (NSs) we separate short gamma-ray bursts (GRBs) in two sub-classes. The ones with $E_{iso}\lesssim10^{52}$ erg coalesce to form a massive NS and are indicated as short gamma-ray flashes (S-GRFs). The hardest, with $E_{iso}\gtrsim10^{52}$ erg, coalesce to form a black hole (BH) and are indicated as genuine short-GRBs (S-GRBs). Within the fireshell model, S-GRBs exhibit three different components: the P-GRB emission, observed at the transparency of a self-accelerating baryon-$e^+e^-$ plasma; the prompt emission, originating from the interaction of the accelerated baryons with the circumburst medium; the high-energy (GeV) emission, observed after the P-GRB and indicating the formation of a BH. GRB 090510 gives the first evidence for the formation of a Kerr BH or, possibly, a Kerr-Newman BH. Its P-GRB spectrum can be fitted by a convolution of thermal spectra whose origin can be traced back to an axially symmetric dyadotorus. A large value of the angular momentum of the newborn BH is consistent with the large energetics of this S-GRB, which reach in the 1--10000 keV range $E_{iso}=(3.95\pm0.21)\times10^{52}$ erg and in the 0.1--100 GeV range $E_{LAT}=(5.78\pm0.60)\times10^{52}$ erg, the most energetic GeV emission ever observed in S-GRBs. The theoretical redshift $z_{th}=0.75\pm0.17$ that we derive from the fireshell theory is consistent with the spectroscopic measurement $z=0.903\pm0.003$, showing the self-consistency of the theoretical approach. All S-GRBs exhibit GeV emission, when inside the Fermi-LAT field of view, unlike S-GRFs, which never evidence it. The GeV emission appears to be the discriminant for the formation of a BH in GRBs, confirmed by their observed overall energetics.

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