On the Induced Gravitational Collapse

The induced gravitational collapse (IGC) paradigm has been applied to explain the long gamma ray burst (GRB) associated with type Ic supernova, and recently the Xray flashes (XRFs). The progenitor is a binary systems of a carbon-oxygen core (CO) and a neutron star (NS). The CO core collapses and undergoes a supernova explosion which triggers the hypercritical accretion onto the NS companion (up to 10-2 M⊙s-1). For the binary driven hypernova (BdHNe), the binary system is enough bound, the NS reach its critical mass, and collapse to a black hole (BH) with a GRB emission characterized by an isotropic energy Eiso > 1052 erg. Otherwise, for binary systems with larger binary separations, the hypercritical accretion onto the NS is not sufficient to induced its gravitational collapse, a X-ray flash is produced with Eiso < 1052 erg. We’re going to focus in identify the binary parameters that limits the BdHNe systems with the XRFs systems.

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Induced gravitational collapse in FeCO Core–Neutron star binaries and Neutron star–Neutron star binary mergers

International Journal of Modern Physics A ◽

10.1142/s0217751x15450232 ◽

2015 ◽

Vol 30 (28n29) ◽

pp. 1545023

Author(s):

R. Ruffini ◽

Y. Aimuratov ◽

C. L. Bianco ◽

M. Enderli ◽

M. Kovacevic ◽

...

Keyword(s):

Neutron Star ◽

Gravitational Collapse ◽

Binary Systems ◽

Recent Progress ◽

Gamma Ray ◽

Critical Mass ◽

Gamma Ray Bursts ◽

New Paradigm ◽

Binary Mergers ◽

Star Binary

We review the recent progress in understanding the nature of gamma-ray bursts (GRBs). The occurrence of GRB is explained by the Induced Gravitational Collapse (IGC) in FeCO Core–Neutron star binaries and Neutron star–Neutron star binary mergers, both processes occur within binary system progenitors. Making use of this most unexpected new paradigm, with the fundamental implications by the neutron star (NS) critical mass, we find that different initial configurations of binary systems lead to different GRB families with specific new physical predictions confirmed by observations.

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The binary systems associated with short and long gamma-ray bursts and their detectability

International Journal of Modern Physics D ◽

10.1142/s0218271817300166 ◽

2017 ◽

Vol 26 (09) ◽

pp. 1730016 ◽

Cited By ~ 3

Author(s):

Jorge A. Rueda ◽

Y. Aimuratov ◽

U. Barres de Almeida ◽

L. Becerra ◽

C. L. Bianco ◽

...

Keyword(s):

Neutron Star ◽

Gravitational Collapse ◽

Binary Systems ◽

Gamma Ray ◽

Critical Mass ◽

Compact Object ◽

Gamma Ray Bursts ◽

Black Hole Binaries ◽

Long Duration

Short and long-duration gamma-ray bursts (GRBs) have been recently sub-classified into seven families according to the binary nature of their progenitors. For short GRBs, mergers of neutron star binaries (NS–NS) or neutron star-black hole binaries (NS-BH) are proposed. For long GRBs, the induced gravitational collapse (IGC) paradigm proposes a tight binary system composed of a carbon–oxygen core (CO[Formula: see text]) and a NS companion. The explosion of the CO[Formula: see text] as supernova (SN) triggers a hypercritical accretion process onto the NS companion which might reach the critical mass for the gravitational collapse to a BH. Thus, this process can lead either to a NS-BH or to NS–NS depending on whether or not the accretion is sufficient to induce the collapse of the NS into a BH. We shall discuss for the above compact object binaries: (1) the role of the NS structure and the equation-of-state on their final fate; (2) their occurrence rates as inferred from the X and gamma-ray observations; (3) the expected number of detections of their gravitational wave (GW) emission by the Advanced LIGO interferometer.

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Evolution of an electron-positron plasma produced by induced gravitational collapse in binary-driven hypernovae

EPJ Web of Conferences ◽

10.1051/epjconf/201816804009 ◽

2018 ◽

Vol 168 ◽

pp. 04009 ◽

Cited By ~ 1

Author(s):

J. D. Melon Fuksman ◽

L. Becerra ◽

C. L. Bianco ◽

M. Karlica ◽

M. Kovacevic ◽

...

Keyword(s):

Black Hole ◽

Neutron Star ◽

Gravitational Collapse ◽

Gamma Ray ◽

Gamma Ray Bursts ◽

Relativistic Hydrodynamics ◽

X Ray ◽

The Past ◽

Electron Positron ◽

Prompt Emission

The binary-driven hypernova (BdHN) model has been introduced in the past years, to explain a subfamily of gamma-ray bursts (GRBs) with energies Eiso ≥ 1052 erg associated with type Ic supernovae. Such BdHNe have as progenitor a tight binary system composed of a carbon-oxigen (CO) core and a neutron star undergoing an induced gravitational collapse to a black hole, triggered by the CO core explosion as a supernova (SN). This collapse produces an optically-thick e+e- plasma, which expands and impacts onto the SN ejecta. This process is here considered as a candidate for the production of X-ray flares, which are frequently observed following the prompt emission of GRBs. In this work we follow the evolution of the e+e- plasma as it interacts with the SN ejecta, by solving the equations of relativistic hydrodynamics numerically. Our results are compatible with the Lorentz factors estimated for the sources that produce the flares, of typically Γ ≲ 4.

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A Machine Learning Approach For Classifying Low-mass X-ray Binaries Based On Their Compact Object Nature

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3899 ◽

2020 ◽

Author(s):

R Pattnaik ◽

K Sharma ◽

K Alabarta ◽

D Altamirano ◽

M Chakraborty ◽

...

Keyword(s):

Machine Learning ◽

Black Hole ◽

Neutron Star ◽

Binary Systems ◽

Compact Object ◽

X Ray ◽

Average Accuracy ◽

Machine Learning Approach ◽

Low Mass ◽

X Ray Binaries

Abstract Low Mass X-ray binaries (LMXBs) are binary systems where one of the components is either a black hole or a neutron star and the other is a less massive star. It is challenging to unambiguously determine whether a LMXB hosts a black hole or a neutron star. In the last few decades, multiple observational works have tried, with different levels of success, to address this problem. In this paper, we explore the use of machine learning to tackle this observational challenge. We train a random forest classifier to identify the type of compact object using the energy spectrum in the energy range 5-25 keV obtained from the Rossi X-ray Timing Explorer archive. We report an average accuracy of 87±13% in classifying the spectra of LMXB sources. We further use the trained model for predicting the classes for LMXB systems with unknown or ambiguous classification. With the ever-increasing volume of astronomical data in the X-ray domain from present and upcoming missions (e.g., SWIFT, XMM-Newton, XARM, ATHENA, NICER), such methods can be extremely useful for faster and robust classification of X-ray sources and can also be deployed as part of the data reduction pipeline.

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Evidence from high-mass X-ray binaries that Galactic WR components of WR+O binaries end their life with a supernova explosion

Astronomy and Astrophysics ◽

10.1051/0004-6361/201937253 ◽

2020 ◽

Vol 636 ◽

pp. A99 ◽

Cited By ~ 3

Author(s):

D. Vanbeveren ◽

N. Mennekens ◽

E. P. J. van den Heuvel ◽

J. Van Bever

Keyword(s):

Black Hole ◽

Neutron Star ◽

Supernova Explosion ◽

Solar Neighborhood ◽

High Mass ◽

Population Number ◽

X Ray ◽

Theoretical Population ◽

X Ray Binaries

Context. Theoretical population number studies of binaries with at least one black hole (BH) component obviously depend on whether or not BHs receive a (natal) kick during their formation. Aims. Several observational facts seem to indicate that BHs do indeed receive a kick during their formation. In the present paper, we discuss additional evidence of this. Methods. The progenitors of wind-fed high-mass X-ray binaries (HMXB) with a BH component (BH HMXB) are WR+OB binaries where the Wolf–Rayet (WR) star will finally collapse and form the BH. Starting from the observed population of WR+OB binaries in the solar neighborhood, we predict the population of wind-fed BH HMXBs as a function of the BH-natal kick. Results. The simulations reveal that when WR stars collapse into a BH with a zero or low kick, we should expect 100 or more wind-fed BH HMXBs in the solar neighborhood, whereas only one is observed (Cyg X-1). We consider this as evidence that either WR components in binaries end their life as a neutron star or that they collapse into BHs, both accompanied by a supernova explosion imparting significant (natal) kicks.

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ON THE THEORY OF GAMMA RAY BURSTS AND HYPERNOVAE: THE BLACK HOLE SOFT X-RAY TRANSIENT SOURCES

International Journal of Modern Physics A ◽

10.1142/s0217751x03012266 ◽

2003 ◽

Vol 18 (04) ◽

pp. 527-576 ◽

Cited By ~ 3

Author(s):

CHANG-HWAN LEE ◽

GERALD E. BROWN

Keyword(s):

Mass Transfer ◽

Black Hole ◽

Mass Loss ◽

Evolutionary History ◽

Main Sequence ◽

Gamma Ray ◽

Supernova Explosion ◽

Sequence Evolution ◽

X Ray ◽

Black Hole Binaries

We show that a common evolutionary history can produce the black hole binaries in the Galaxy in which the black holes have masses of ~ 5 - 10M⊙. In the black hole binaries with low-mass, ≲ 2.5M⊙ ZAMS (zero age main sequence) companions, the latter remain in main sequence during the active stage of soft X-ray transients (SXT's), most of them being of K or M classification. In two intermediate cases, IL Lupi and Nova Scorpii with ZAMS ~ 2.5M⊙ companions the orbits are greatly widened because of large mass loss in the explosion forming the black hole, and whereas these companions are in late main sequence evolution, they are close to evolving. Binaries with companion ZAMS masses ≳ 3M⊙ are initially "silent" until the companion begins evolving across the Herzsprung gap. We provide evidence that the narrower, shorter period binaries, with companions now in main sequence, are fossil remnants of gamma ray bursters (GRB's). We also show that the GRB is generally accompanied by a hypernova explosion (a very energetic supernova explosion). We further show that the binaries with evolved companions are good models for some of the ultraluminous X-ray sources (ULX's) recently seen by Chandra in other galaxies. The great regularity in our evolutionary history, especially the fact that most of the companions of ZAMS mass ≲ 2.5M⊙ remain in main sequences as K or M stars can be explained by the mass loss in common envelope evolution to be Case C; i.e. to occur only after core He burning has finished. Since our argument for Case C mass transfer is not generally understood in the community, we add an appendix, showing that with certain assumptions which we outline we can reproduce the regularities in the evolution of black hole binaries by Case C mass transfer.

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Origin of High Velocity Pulsar and Soft Gamma Ray Repeaters

International Astronomical Union Colloquium ◽

10.1017/s0252921100041890 ◽

1996 ◽

Vol 160 ◽

pp. 359-360

Author(s):

Hitoshi Hanami

Keyword(s):

Neutron Star ◽

Binary System ◽

High Velocity ◽

Relative Velocity ◽

Gamma Ray ◽

Center Of Mass ◽

Supernova Explosion ◽

Close Binary System ◽

Close Binary ◽

X Ray

AbstractWe consider a close binary system with separation ≃ 0.2 R⊙which consists of a (C+O) star of mass ≃ 4 M⊙and a neutron star as a progenitor of soft gamma-ray repeater (SGR) and a high velocity pulsar. After the event of the supernova explosion, both new and old neutron stars have high relative velocity of ≃ 1000km s−1to the center of mass of the ejecta. SGR activities can be induced by the episodic accretion of the supernova ejecta onto the old neutron star or the strange high rotating pulsar of the new neutron star. Future observations with fine positional resolution can clarify the position ambiguity between the gamma ray and X-ray sources.

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Imprints of r-process heating on fall-back accretion: distinguishing black hole–neutron star from double neutron star mergers

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz644 ◽

2019 ◽

Vol 485 (3) ◽

pp. 4404-4412 ◽

Cited By ~ 6

Author(s):

D Desai ◽

B D Metzger ◽

F Foucart

Keyword(s):

Black Holes ◽

Black Hole ◽

Neutron Star ◽

Gamma Ray ◽

Late Time ◽

X Ray ◽

Power Law Decay ◽

Process Heating ◽

R Process ◽

The Impact

ABSTRACT Mergers of compact binaries containing two neutron stars (NS–NS), or a neutron star and a stellar mass black hole (NS–BH), are likely progenitors of short-duration gamma-ray bursts (SGRBs). A fraction ${\gtrsim } 20{{\ \rm per\ cent}}$ of SGRBs is followed by temporally extended (≳minute-long), variable X-ray emission, attributed to ongoing activity of the central engine. One source of late-time engine activity is fall-back accretion of bound tidal ejecta; however, observed extended emission light curves do not track the naively anticipated, uninterrupted t−5/3 power-law decay, instead showing a lull or gap in emission typically lasting tens of seconds after the burst. Here, we re-examine the impact of heating due to rapid neutron capture (r-process) nucleosynthesis on the rate of the fall-back accretion, using ejecta properties extracted from numerical relativity simulations of NS–BH mergers. Heating by the r-process has its greatest impact on marginally bound matter, hence its relevance to late-time fall-back. Depending on the electron fraction of the ejecta and the mass of the remnant black hole, r-process heating can imprint a range of fall-back behaviour, ranging from temporal gaps of up to tens of seconds to complete late-time cut-off in the accretion rate. This behaviour is robust to realistic variations in the nuclear heating experienced by different parts of the ejecta. Central black holes with masses ${\lesssim } 3\, \mathrm{M}_{\odot }$ typically experience absolute cut-offs in the fall-back rate, while more massive ${\gtrsim } 6\!-\!8\, \mathrm{M}_{\odot }$ black holes instead show temporal gaps. We thus propose that SGRBs showing extended X-ray emission arise from NS–BH, rather than NS–NS, mergers. Our model implies an NS–BH merger detection rate by LIGO that, in steady state, is comparable to or greater than that of NS–NS mergers.

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What can we learn from GRBs?

EPJ Web of Conferences ◽

10.1051/epjconf/201816801015 ◽

2018 ◽

Vol 168 ◽

pp. 01015

Author(s):

Marco Muccino ◽

Remo Ruffini ◽

Yerlan Aimuratov ◽

Laura M. Becerra ◽

Carlo L. Bianco ◽

...

Keyword(s):

Black Hole ◽

Neutron Star ◽

Binary System ◽

Gravitational Collapse ◽

White Dwarf ◽

Gamma Ray ◽

Gamma Ray Bursts ◽

Binary Nature ◽

Accretion Process

We review our recent results on the classification of long and short gamma-ray bursts (GRBs) in different subclasses. We provide observational evidences for the binary nature of GRB progenitors. For long bursts the induced gravitational collapse (IGC) paradigm proposes as progenitor a tight binary system composed of a carbon-oxygen core (COcore) and a neutron star (NS) companion; the supernova (SN) explosion of the COcore triggers a hypercritical accretion process onto the companion NS. For short bursts a NS–NS merger is traditionally adopted as the progenitor. We also indicate additional sub-classes originating from different progenitors: (COcore)–black hole (BH), BH–NS, and white dwarf–NS binaries. We also show how the outcomes of the further evolution of some of these sub-classes may become the progenitor systems of other sub-classes.

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