We present recipes to diagnose the fireball of gamma-ray bursts (GRBs) by combining observations of e± pair signatures (the pair annihilation line and the cutoff energy due to the pair creation process). Our recipes are largely model-independent and extract information even from the nondetection of either pair signature. We evaluate physical quantities such as the Lorentz factor, optical depth, and pair-to-baryon ratio only from the observable quantities. In particular, we can test whether the prompt emission of GRBs comes from the pair/baryonic photosphere or not. The future Gamma-Ray Large Area Space Telescope (GLAST) satellite will provide us with good chances to use our recipes via either detection or nondetection of pair signatures.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science