Possible models for the high-energy transient GB790107

The discovery of rapid repetitive soft γ-ray burst events on time-scales as short as seconds from GB790107 by Laros and co-workers and Atteia and co-workers^1-3 may have important implications for our understanding of the γ-ray burst mechanism. Although there is a general consensus that the high-energy transient phenomenon in the X-ray range known as Type I X-ray bursts can be successfully explained in terms of a thermonuclear flash in the accreted surface layers of a neutron star^4,5, the theory for γ-ray bursts is still controversial. In fact, it is possible (perhaps even likely) that there is more than one mechanism by which the γ-ray burst phenomenon can be understood. The properties of GB790107 place severe constraints on the viability of models proposed for the typical γ-ray burst events as applied to this soft γ-ray repeater. Here we review the various models proposed for γ-ray bursts and show that a model involving a comet cloud around a neutron star is consistent with the observational data.