Astron. Astrophys. Suppl. Ser.
Volume 138, Number 3, September 1999Gamma-Ray Bursts in the Afterglow Era Contents Rome, November 3-6, 1998
|Page(s)||525 - 526|
|Published online||15 September 1999|
Spectral evolution of GRBs and the "death line” of the synchrotron shock model
International School for Advanced Studies (SISSA), Via Beirut 2-4, 34013 Trieste, Italy
Send offprint request to: H. Papathanassiou
Accepted: 12 March 1999
I calculate spectral evolution series for pulses of GRBs, in the BATSE spectral range, for continuous particle injection and cooling by synchrotron, inverse Compton, and adiabatic expansion. The hydrodynamic properties of the relativistic outflow are homogeneous across the emitting region which is a conical jet. The flow is viewed at an angle off its symmetry axis; time delays are taken into account. I discuss the low energy slope part of the spectrum, in view of the recent claim of photon slopes in bright BATSE bursts that are inconsistent with the optically thin synchrotron shock model (SSM).
Key words: radiation mechanisms: non-thermal / gamma-rays: bursts / gamma-rays: theory / relativity
© European Southern Observatory (ESO), 1999