Multi-Component Time-Resolved Analysis of Short and Long GRB Prompt Emission from Optical to Gamma-Ray

The Band function traditionally used for Gamma Ray Bursts (GRB) often fails to fit their prompt emission spectra. Our new model composed of three separate components provides an excellent description of the time-resolved prompt emission of both short and long GRBs: a thermal-like and two non-thermal components. For the first time, analysis of GRBs with correlated optical and gamma-ray prompt emission shows that our new model describes very accurately the whole broadband spectrum from the optical regime to higher energy gamma rays. In addition, this model enables a new luminosity/hardness relation intrinsic to one of the non-thermal components, which is promising for establishing GRBs as standard candles. This relation will be used to (i) constrain the mechanisms powering GRB jets, (ii) estimate GRB distances from gamma-ray data only (very useful in the Era of multi-messenger astrophysics and gravitational-wave searches), (iii) probe the early Universe, and (iv) constrain the cosmological parameters. I will present this new unified model using analysis of GRBs detected with various observatories and instruments such as Fermi, CGRO/BATSE and the combination of the three instruments onboard Swift and Suzaku/WAM. I will discuss here the striking similarities of GRB spectral shapes, whose components inform on the nature of the prompt emission, as well as the possible universality of the proposed luminosity/hardness relation in the context of our new model.