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Browsing by Author "Joshi, Pankaj S."

Browsing by Author "Joshi, Pankaj S."

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  • All black holes in Lemaˆıtre-Tolman-Bondi inhomogeneous dust collapse 
    Joshi, Pankaj S.; Malafarina, D. (2015-09-08)
    Within the Lemaˆıtre-Tolman-Bondi formalism for gravitational collapse of inhomogeneous dust we analyze the parameter space that leads to the formation of a globally covered singularity (i.e. a black hole) when some ...
  • Circular geodesics and accretion disks in Janis-Newman-Winicour and Gamma metric 
    Chowdhury, Anirban N.; Patil, Mandar; Malafarina, D.; Joshi, Pankaj S. (2012-04-19)
    We study here circular timelike geodesics in the Janis-Newman-Winicour and Gamma metric spacetimes which contain a strong curvature naked singularity and reduce to the Schwarzschild metric for a specific value of one of ...
  • Compact objects from gravitational collapse: an analytical toy model 
    Malafarina, D.; Joshi, Pankaj S. (2015)
    We develop here a procedure to obtain regular static configurations as resulting from dynamical gravitational collapse of a massive matter cloud in general relativity. Under certain general physical assumptions for the ...
  • Distinguishing black holes from naked singularities through their accretion disk properties 
    Joshi, Pankaj S.; Malafarina, D.; Narayan, Ramesh (2014-05-06)
    We show that, in principle, a slowly evolving gravitationally collapsing perfect fluid cloud can asymptotically settle to a static spherically symmetric equilibrium configuration with a naked singularity at the center. We ...
  • Equilibrium configurations from gravitational collapse 
    Joshi, Pankaj S.; Narayan, Ramesh; Malafarina, D. (2011-11-18)
    We develop here a new procedure within Einstein’s theory of gravity to generate equilibrium configurations that result as the final state of gravitational collapse from regular initial conditions. As a simplification, we ...
  • Genericity aspects in gravitational collapse to black holes and naked singularities 
    Joshi, Pankaj S.; Malafarina, D.; Saraykar, Ravindra V. (2012-07-04)
    We investigate here the genericity and stability aspects for naked singularities and black holes that arise as the final states for a complete gravitational collapse of a spherical massive matter cloud. The form of the ...
  • Gravitational Collapse of Inhomogenous Perfect Fluid 
    Satin, Seema; Malafarina, D.; Joshi, Pankaj S. (2014)
    We study the complete gravitational collapse of a class of inhomogeneous perfect fluid models obtained by introducing small radial perturbations in an otherwise homogeneous matter cloud. The key feature that we assume for ...
  • Gravitational collapse with tangential pressure 
    Malafarina, D.; Joshi, Pankaj S. (2011-05-06)
    Using the general formalism for spherical gravitational collapse developed in [1], we investigate here the final fate of a spherical distribution of a matter cloud, where radial pressures vanish but tangential pressures ...
  • Instability of black hole formation under small pressure perturbations 
    Joshi, Pankaj S.; Malafarina, D. (2012-11-14)
    We investigate here the spectrum of gravitational collapse endstates when arbitrarily small perfect fluid pressures are introduced in the classic black hole formation scenario as described by Oppenheimer, Snyder and Datt ...
  • Naked Singularities as Particle Accelerators II 
    Patil, Mandar; Joshi, Pankaj S.; Malafarina, D. (2011-02-14)
    We generalize here our earlier results on particle acceleration by naked singularities. We showed recently [1] that the naked singularities that form due to gravitational collapse of massive stars provide a suitable ...
  • Recent developments in gravitational collapse and spacetime singularities 
    Joshi, Pankaj S.; Malafarina, D. (2012-01-19)
    It is now known that when a massive star collapses under the force of its own gravity, the final fate of such a continual gravitational collapse will be either a black hole or a naked singularity under a wide variety of ...
  • Scalar field collapse and cosmic censorship 
    Goswami, Rituparno; Joshi, Pankaj S.; Malafarina, D. (2012-02-28)
    We analyze here the final fate of complete gravitational collapse of a massless scalar field within general relativity. A class of dynamical solutions with initial data close to the Friedmann-Lemaˆıtre-Robertson-Walker ...
  • The instability of black hole formation in gravitational collapse 
    Joshi, Pankaj S.; Malafarina, D. (2011-01-11)
    We consider here the classic scenario given by Oppenheimer, Snyder, and Datt, for the gravitational collapse of a massive matter cloud, and examine its stability under the introduction of small tangential stresses. We show, ...
  • Thermodynamics and gravitational collapse 
    Malafarina, D.; Joshi, Pankaj S. (2011-06-19)
    It is known now that a typical gravitational collapse in general relativity, evolving from regular initial data and under physically reasonable conditions would end in either a black hole or a naked singularity final state. ...