Spectral-Luminosity relation within individual Fermi GRBs

Understand

We study the spectra of all long Gamma Ray Bursts (GRBs) of known redshift detected by the Fermi satellite.

• Their fluxes and fluences are large enough to allow a time dependent study of their spectral characteristics in the 8 keV-1 MeV energy range.
• We find that the peak energy Ep of their EL(E) spectrum correlates with the luminosity in a remarkable tight way within individual bursts.
• This time resolved Ep-Liso correlation is very similar for all the considered bursts, and has a slope and normalisation similar to the analogous Ep-Liso correlation defined by the time integrated spectra of different bursts detected by several different satellites.