Abstract
Considered here is the acceleration and heating of relativistic outflow by local magnetic energy dissipation process in Poynting-flux dominated outflow. Adopting the standard assumption that the reconnection rate scales with the Alfven speed, I show here that the fraction of energy dissipated as thermal photons cannot exceed (13γ - 14)-1 = 30% (for adiabatic index γ = 4 3) of the kinetic energy at the photosphere. Even in the most radiatively efficient scenario, the energy released as non-thermal photons during the prompt phase is at most equal to the kinetic energy of the outflow. These results imply that calorimetry of the kinetic energy that can be done during the afterglow phase could be used to constrain the magnetization of gamma-ray bursts (GRB) outflows. I discuss the recent observational status and its implications on constraining the magnetization in GRB outflows.
| Original language | English |
|---|---|
| Article number | 200 |
| Journal | Astrophysical Journal |
| Volume | 850 |
| Issue number | 2 |
| DOIs | |
| State | Published - 1 Dec 2017 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2017. The American Astronomical Society. All rights reserved.
Funding
A.P. thanks Damien Begue, Brad Cenko, Amir Levinson, Yuri Lyubarski, Raffaella Margutti, and Bing Zhang for useful comments. I further thank the anonymous referee for useful comments that helped improve this manuscript. This research was partially supported by the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 618499. I further acknowledge support from NASA under grant #NNX12AO83G.
| Funders | Funder number |
|---|---|
| National Aeronautics and Space Administration | #NNX12AO83G |
| Seventh Framework Programme | 618499 |
| Seventh Framework Programme |
Keywords
- (Stars:) Gamma-ray burst: general
- magnetic reconnection
- magnetohydrodynamics (MHD)
- plasmas
- radiation mechanisms: non-thermal
- radiation mechanisms: thermal