Michalowski, M: Spectral Energy Distributions of Gamma Ray B

This work is concentrated on the fitting of the Spectral Energy Distribution (SED) templates to the broad-band observational data of Gamma Ray Bursts (GRB) host galaxies, which were bright in submillimetre and/or radio wavelengths, namely hosts of GRB 980703, GRB 000210, GRB 000418 and GRB 010222. This is the first successful entire SED fitting, from optical to radio wavelengths, achieved for GRB hosts. I present constraints on their properties, including the need for high dust temperatures, high star formation rates (SFR) and low ages. I estimated very conservative and robust lower limits on the dust temperatures in a range from T 29 K to T 59 K. Their SFRs derived from infrared emission range from 179 to 1211 solar masses per year and it places GRB hosts in a category of highly star-forming galaxies. I propose that the seeming contradiction of high SFRs and blue optical colors of GRB hosts can be explained by their low ages in a range from 90 Myr to 2 Gyr.