A Kinematic Model for Gamma Ray Bursts and Symmetric Jets

Gamma ray bursts (GRB) occur at random points in the sky at cosmological distances. They emit intense γ rays for a brief period. The spectrum then evolves through X–ray, optical region to possibly radio frequency. Though there are some models, the origin and time evolution of GRB are not well understood. Extragalactic radio sources also exhibit a baffling array of features that are poorly understood – the core emission in ultraviolet region, lobes in RF range, transient γ and X–ray emissions etc. These two phenomena appear to be very different, but the time evolution of the core emission of radio sources is essentially the same as GRBs, though with different time constants. Here, we present a model unifying GRB and roughly symmetric radio sources based on light travel time effect and superluminality. The light travel time effect influences the way we perceive superluminal motion. An object, moving across our field of vision at superluminal speeds, will appear to us as two objects receding from a single point. The time evolution of the Doppler shifted radiation of such a superluminal object bears remarkable similarity to that of GRB and radio sources. Based on these observations, we derive a kinematic model for radio sources and GRBs and explain the puzzling features listed above. Furthermore, we predict the angular motion of the hotspots or knots in the jets and compare it to the proper motions reported in the literature (Biretta et al., 1999). We also compare the proper motion of a microquasar (Mirabel and Rodŕiguez, 1999) with our model and show excellent agreement. Our model also explains the observed blue/UV spectrum (and its time evolution) of the core region and the RF spectrum of the lobes, and why the radio sources appear to be associated with galactic nuclei. We make other quantitative predictions, which can be verified.