Relationship Between the Gamma-Ray and X-Ray Data of the Swift GRBs

Using the canonical correlation analysis of the multivariate statistics we investigate the interrelation between the gamma-ray (the fluence, the 1 s peakflux and the duration) and the X-ray (the early flux, the flux after 24 hours, the decay index, the spectral index and the H I column density) data. By computing the canonical correlations and variables we show that there is a significant interrelation between the gamma-ray and the X-ray data. We computed the canonical loadings, i.e., the correlations of the canonical variables with the original ones. The canonical loadings reveal that the gamma-ray fluence and the early X-ray flux give the strongest contribution to the correlation in contrast to the X-ray decay index and spectral index. A strong contribution of the H I column density to the correlation is found. Accepting for the long GRBs the collapsar model, this effect may be interpreted as an indication for the ejection of a H I envelope by the progenitor during the GRB.