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Long gamma-ray bursts (GRBs) are believed to be related to the explosion of type Ic supernovae, which have been stripped of their hydrogen and helium envelopes. There appear to be two types of these explosions: those which are approximately spherical (GRB980425/1998bw), and which are associated with weak bursts, and the classical GRBs which generate ultrarelativistic jets (GRB030329/SN2003dh). If this bimodality is real Swift will provide a clear evidence for it. We propose that classical powerful GRBs, which generate ultrarelativistic outflows, are a result of a formation of quark stars. Quark stars may provide an additional energy for the explosion of SN Ic, but far more important is a creation of a surface which acts as a membrane which cannot be penetrated by baryons. A surface of a quark star allows only ultrarelativistic matter to escape: photons, neutrinos, electron -- positron pairs and magnetic fields. The formation of a quark star follows the initial core collapse in several minutes. Possible evidence for this time delay is provided by BATSE precursors to GRBs, as analyzed by Lazzati (2005).
We present predictions of centimeter and millimeter radio emission from reverse shocks in the early afterglows of gamma-ray bursts with the goal of determining their detectability with current and future radio facilities. Using a range of GRB propert
The constancy of light speed is a basic assumption in Einsteins special relativity, and consequently the Lorentz invariance is a fundamental symmetry of space-time in modern physics. However, it is speculated that the speed of light becomes energy-de
LOFAR, the Low Frequency Array, is an innovative new radio telescope currently under construction in the Netherlands. With its continuous monitoring of the radio sky we expect LOFAR will detect many new transient events, including GRB afterglows and
We propose a model for short duration gamma-ray bursts (sGRBs) based on the formation of a quark star after the merger of two neutron stars. We assume that the sGRB central engine is a proto-magnetar, which has been previously invoked to explain the
The study of the early high-energy emission from both long and short Gamma-ray bursts has been revolutionized by the Swift mission. The rapid response of Swift shows that the non-thermal X-ray emission transitions smoothly from the prompt phase into