Physical Constraints From Broadband Afterglow Fits:GRB000926 as an Example

We develop a model to fit the broadband afterglows of GRBs from the intrinsic parameters of the fireballs synchrotron emission, and apply it to a few well-studied events, with the goal of constraining the intrinsic variability of GRB parameters. We give an example here of fitting to the recent bright event GRB000926.