Globally visible singularity in an astrophysical setup

Abstract The global visibility of a singularity as an end state of the gravitational collapse of a spherically symmetric pressureless cloud is investigated. We show the existence of a non-zero measured set of parameters: the total mass and the initial mean density of the collapsing cloud, giving rise to a physically strong globally visible singularity as the end state for a fixed velocity function. The existence of such a set indicates that such singularity is stable under small perturbation in the initial data causing its existence. This is true for marginally as well as non-marginally bound cases. The possibility of the presence of such suitable parameters in the astrophysical setup is then studied: 1) The singularities’ requirements at the center of the M87 galaxy and at the center of our galaxy (SgrA*) to be globally visible are discussed in terms of the initial size of the collapsing cloud forming them, presuming that such singularities are formed due to gravitational collapse. 2) The requirement for the primordial singularities formed due to a collapsing configuration after getting detached from the background universe, at the time of matter-dominated era just after the time of matter-radiation equality, to be globally visible, is discussed. 3) The scenario of the collapse of a neutron star after reaching a critical mass, which is achieved by accreting the supernova ejecta expelled by its binary companion core progenitor, is considered. The primary aim of this paper is to show that globally visible singularities can form in astrophysical setups under appropriate circumstances.

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Critical mass phenomenon for a chemotaxis kinetic model with spherically symmetric initial data

Annales de l Institut Henri Poincaré C Analyse non linéaire ◽

10.1016/j.anihpc.2009.02.001 ◽

2009 ◽

Vol 26 (5) ◽

pp. 1871-1895 ◽

Cited By ~ 16

Author(s):

Nikolaos Bournaveas ◽

Vincent Calvez

Keyword(s):

Kinetic Model ◽

Initial Data ◽

Critical Mass ◽

Spherically Symmetric ◽

Symmetric Initial Data

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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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Initial data and the end state of spherically symmetric gravitational collapse

Classical and Quantum Gravity ◽

10.1088/0264-9381/16/1/003 ◽

1999 ◽

Vol 16 (1) ◽

pp. 41-59 ◽

Cited By ~ 73

Author(s):

P S Joshi ◽

I H Dwivedi

Keyword(s):

Initial Data ◽

Gravitational Collapse ◽

Spherically Symmetric

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On the Induced Gravitational Collapse

EPJ Web of Conferences ◽

10.1051/epjconf/201816802005 ◽

2018 ◽

Vol 168 ◽

pp. 02005

Author(s):

Laura M. Becerra ◽

Carlo Bianco ◽

Chris Fryer ◽

Jorge Rueda ◽

Remo Ruffini

Keyword(s):

Black Hole ◽

Neutron Star ◽

Gravitational Collapse ◽

Binary Systems ◽

Gamma Ray ◽

Critical Mass ◽

Supernova Explosion ◽

Isotropic Energy ◽

X Ray ◽

Binary Separations

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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Boundedness of Solutions to a Parabolic-Elliptic Keller–Segel Equation in ℝ2 with Critical Mass

Advanced Nonlinear Studies ◽

10.1515/ans-2017-6025 ◽

2018 ◽

Vol 18 (2) ◽

pp. 337-360

Author(s):

Toshitaka Nagai ◽

Tetsuya Yamada

Keyword(s):

Cauchy Problem ◽

Initial Data ◽

Elliptic System ◽

Total Mass ◽

Critical Mass ◽

The Other ◽

Boundedness Of Solutions ◽

Nonnegative Solutions ◽

The Cauchy Problem ◽

Mass Case

AbstractWe consider the Cauchy problem for a parabolic-elliptic system in{\mathbb{R}^{2}}, called the parabolic-elliptic Keller–Segel equation, which appears in various fields in biology and physics. In the critical mass case where the total mass of the initial data is{8\pi}, the unboundedness of nonnegative solutions to the Cauchy problem was shown by Blanchet, Carrillo and Masmoudi [7] under some conditions on the initial data, on the other hand, conditions for boundedness were given by Blanchet, Carlen and Carrillo [6] and López-Gómez, Nagai and Yamada [23]. In this paper, we investigate further the boundedness of nonnegative solutions.

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CAN WE SEE NAKED SINGULARITIES?

International Journal of Modern Physics D ◽

10.1142/s0218271809015990 ◽

2009 ◽

Vol 18 (14) ◽

pp. 2083-2092

Author(s):

SHRIRANG S. DESHINGKAR

Keyword(s):

Initial Data ◽

Gravitational Collapse ◽

Energy Condition ◽

Matter Field ◽

Specific Form ◽

Weak Energy Condition ◽

Spherically Symmetric ◽

Naked Singularities ◽

Physical Consequences

We study singularities which can form in a spherically symmetric gravitational collapse of a general matter field obeying weak energy condition. We show that null naked singularities that form in such a collapse can never be observed. No energy can come out of these singularities; thus they will have no physical consequences outside. As this happens for any null singularity, we do not need to assume specific form of matter and establish role of initial data. Hence our result is very general.

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The asymptotic behaviour in Schwarzschild time of Vlasov matter in spherically symmetric gravitational collapse

Mathematical Proceedings of the Cambridge Philosophical Society ◽

10.1017/s0305004109990454 ◽

2010 ◽

Vol 149 (1) ◽

pp. 173-188 ◽

Cited By ~ 6

Author(s):

HÅKAN ANDRÉASSON ◽

GERHARD REIN

Keyword(s):

Initial Data ◽

Asymptotic Behaviour ◽

Event Horizon ◽

Gravitational Collapse ◽

Careful Analysis ◽

Necessary Condition ◽

Spherically Symmetric ◽

Geodesic Completeness ◽

Global Existence Of Solutions ◽

Outer Domain

AbstractGiven a static Schwarzschild spacetime of ADM mass M, it is well known that no ingoing causal geodesic starting in the outer domain r > 2M will cross the event horizon r = 2M in finite Schwarzschild time. We show that in gravitational collapse of Vlasov matter this behaviour can be very different. We construct initial data for which a black hole forms and all matter crosses the event horizon as Schwarzschild time goes to infinity, and show that this is a necessary condition for geodesic completeness of the event horizon. In addition to a careful analysis of the asymptotic behaviour of the matter characteristics our proof requires a new argument for global existence of solutions to the spherically symmetric Einstein–Vlasov system in an outer domain, since our initial data have non-compact support in the radial momentum variable and previous methods break down.

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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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