Multi-wavelength observations of afterglow of GRB080319B and the modeling constraints

Abstract

Context. We present observations of the afterglow of GRB 080319B at optical, mm and radio frequencies from a few hours to 67 days after the burst. Aims. To understand the nature of this brightest explosion based on the observed properties and it’s comparison with the afterglow models. Methods. Present observations along with other published multi-wavelength data have been used to study the light-curves and spectral energy distributions of the burst afterglow. Results. Our results show that the observed features of the afterglow fits equally good with the Inter Stellar Matter and the Stellar Wind density profiles of the circum-burst medium. In case of both density profiles, location of the maximum synchrotron frequency νm is below optical and the value of cooling break frequency νc is below X−rays, ∼ 104 s after the burst. Also, the derived value of the Lorentz factor at the time of naked eye brightness is ∼ 300 with the corresponding blast wave size of ∼ 1018 cm. Conclusions. The numerical fit to the multi-wavelength afterglow data constraints the values of physical parameters and the emission mechanism of the burst.