Quantized synchrotron radiation as a cause of γ-ray bursts

Abstract

In the last several years gamma-ray bursts have continued to be a mysterious and intr iguing phenomenon. The most remarkable observational fact is that the onset of radiation is almost instantaneous (< 2.10-4 s) with a subsequent rapid decay (< 0.35). The revealed concentration of their locations in the direction of the galactic center implies that distances to them are large and should be, on the average, a few kpc; the corresponding estimates of the average-energy output from these bursts, (104~ 1041) erg, yield a value of (10 ~9-104~ erg.s -1 for the average luminosity (1). An overall analysis of the observational data suggests that the burst are produced in regions with a gravitat ional potential of (0.1--0.2)c 2 and a magnetic field 2.1012 gauss (2). How does a gamma-ray burst work? Several models have been proposed to explain the energy source of these bursts. Impact models (3) suggest that a solid body (a comet or an asteroid) falls into the surface of a neutron star providing a nearly instantaneous release of energy. Accretion models (4) speculate that either the Eddington limit or a thermonuclear explosion on the surface of a neutron star may provide the explanation. In this note we try to explore quantized magnetic bremsstrahlung radiation in intense magnetic fields from the surface layers of neutron stars as a possible burst mechanism. In intense magnetic fields, when the gyrating radius of the electron is comparable to its de Broglie wave-length, the classical description of electrons is not valid, and a quantization process similar to that for atomic electrons takes place, resulting in discrete energy levels (known as Landau levels) in the motion perpendicular to the magnetic field, but the motion is still free along the field direction. The Landau levels