The extremely high peak energy of GRB 110721A in the context of a dissipative photosphere synchrotron emission model

TL;DR

This paper investigates the exceptionally high peak energy observed in GRB 110721A and demonstrates that dissipative photospheric synchrotron emission models can explain such extreme energies, unlike traditional models.

Contribution

It introduces dissipative photospheric synchrotron models as a viable explanation for the high peak energy in GRB 110721A, challenging previous internal shock and black-body photospheric models.

Findings

Standard black-body photospheric model cannot explain the high peak energy.

Dissipative photospheric synchrotron models can accommodate peak energies around 15 MeV.

Internal shock models are unlikely to account for the observed peak energy.

Abstract

The Fermi observations of GRB 110721A (Axelsson et al. 2012) have revealed an unusually high peak energy ~ 15 MeV in the first time bin of the prompt emission. We find that an interpretation is unlikely in terms of internal shock models, and confirm that a standard black-body photospheric model also falls short. We show that dissipative photospheric synchrotron models ranging from extreme magnetically dominated to baryon dominated dynamics, on the other hand, are able to accommodate such high peak values.