Modelling synchrotron and synchrotron self-Compton emission of gamma-ray burst afterglows from radio to very-high energies

Synchrotron radiation from a decelerating blastwave is widely accepted model of radio to X-ray afterglow emission gamma-ray bursts (GRBs). GeV detected by the Fermi Large Area Telescope (LAT) and duration which extends beyond prompt phase, also compatible with broad features emission. We revisit synchrotron self-Compton (SSC) fit multiwavelength data three bright GRBs, namely GRB~190114C, GRB~130427A GRB~090510. constrain parameters using simultaneous spectral energy distributions at different times light curves frequencies for these bursts. find that constant density interstellar medium favored short GRB~090510, while wind-type environment long GRB~190114C. The sub-TeV component in GRB~190114C MAGIC SSC our modelling. Furthermore we Thomson regime adequate spectra For other two lacking detection, emissions are modeled regime. have used, $\gamma\gamma$ attenuation negligible range compared redshift-dependent extragalactic background light.