A Global Test of a Quasi-universal Gamma-Ray Burst Jet Model through Monte Carlo Simulations

The possibility that long gamma-ray burst (GRB) jets are structured has received growing attention recently, and we have suggested that most GRBs and their softer, less energetic brethren, X-ray flashes (XRFs), can be understood within a quasi-universal structured jet picture, given that the jet structure of each individual burst is a Gaussian or similar function. Here we perform a global test on such a quasi-universal Gaussian-like structured jet by comparing Monte Carlo simulation results with a broad spectrum of observational data. Using the same set of input parameters as in previous work by Zhang and coworkers, we confront the model with more observational constraints. These constraints include the burst redshift distribution, jet break angle distribution, two-dimensional redshift versus jet break angle distribution, luminosity function, and log N- log P distribution. The results indicate that the model is generally compatible with the data. This conclusion, together with our previous tests with the observed jet break angle versus isotropic energy and observed peak energy versus fluence relations, suggests that current long GRB and XRF data are generally consistent with such a quasi-standard energy and quasi-standard angle jet picture. With future homogeneous burst samples (such as the one to be retrieved from the Swift mission), the refined GRB jet structure can be further constrained through a global comparison between various observed and predicted burst property distributions and relations.