Naked Singularities as Possible Candidates for Gamma-ray Bursters

Abstract

Naked singularities appear naturally in dynamically evolving solutions of Einstein equations involving gravitational collapse of radiation, dust and perfect fluids, provided the rate of accretion is less than a critical value. We propose that the gamma-ray bursters (GRBs) are examples of these naked singularity solutions. For illustration, we show that according to solutions involving spherically symmetric collapse of pure radiation field, the energy $E_\gamma$ and the observed duration $\Delta t_o$ of a GRB should satisfy, $\frac{E_\gamma}{\Delta t_o} \leq 4.5 \times 10^{58} \ f_\gamma $ erg sec$^{-1}$, $f_\gamma$ being the fraction ($10^{-2}$ to $10^{-3}$) of energy released as gamma rays. All the presently observed GRBs satisfy this condition; those satisfying the condition close to equality must necessarily be of cosmological origin with the red-shift factor $z$ not exceeding $\sim 2-10$ depending on exact observed flux.