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Physics: Recent submissions

  • 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 ...
  • Singularity avoidance in classical gravity from four-fermion interaction 
    Bambi, Cosimo; Malafarina, D.; Marcian`o, Antonino; Modesto, Leonardo (2014-05-26)
    We derive the dynamics of the gravitational collapse of a homogeneous and spherically symmetric cloud in a classical set-up endowed with a topological sector of gravity and a non-minimal coupling to fermions. The effective ...
  • Can we observationally test the weak cosmic censorship conjecture? 
    Kong, Lingyao; Malafarina, D.; Bambi, Cosimo (2014-08-04)
    In general relativity, gravitational collapse of matter fields ends with the formation of a spacetime singularity, where the matter density becomes infinite and standard physics breaks down. According to the weak cosmic ...
  • 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 ...
  • 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 ...
  • 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 ...
  • 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. ...
  • 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 ...
  • 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 the naked singularity in the Gamma-metric 
    Lochan, K.; Malafarina, D.; Singh, T.P. (2010-09-23)
    We investigate a possible way of establishing a parallel between the third law of black hole mechanics, and the strong version of the third law of thermodynamics. We calculate the surface gravity and area for a naked ...
  • 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 ...