Paz Beniamini

Energies of GRB blast waves and prompt efficiencies as implied by modelling of X-ray and GeV afterglows

We consider a sample of ten GRBs with long lasting (

Formation of double neutron star systems as implied by observations

\gtrsim10^2\rm\,sec

The emission mechanism in magnetically dominated gamma-ray burst outflows

) emission detected by Fermi/LAT and for which X-ray data around

r-process Production Sites as inferred from Eu Abundances in Dwarf Galaxies

1\,

Electrons’ energy in GRB afterglows implied by radio peaks

day are also available. We assume that both the X-rays and the GeV emission are produced by electrons accelerated at the external forward shock, and show that the X-ray and the GeV fluxes lead to very different estimates of the initial kinetic energy of the blast wave. The energy estimated from GeV is on average

Prompt Gamma Ray Burst emission from gradual magnetic dissipation

\sim50

Dark passengers★ in stellar surveys

times larger than the one estimated from X-rays. We model the data (accounting also for optical detections around

Compton echoes from nearby gamma-ray bursts

1\,

Supernovae-generated high-velocity compact clouds

day, if available) to unveil the reason for this discrepancy and find that good modelling within the forward shock model is always possible and leads to two possibilities: either the X-ray emitting electrons (unlike the GeV emitting electrons) are in the slow cooling regime or ii) the X-ray synchrotron flux is strongly suppressed by Compton cooling, whereas, due to the Klein-Nishina suppression, this effect is much smaller at GeV energies. In both cases the X-ray flux is no longer a robust proxy for the blast wave kinetic energy. On average, both cases require weak magnetic fields (

CONSTRAINTS ON THE SYNCHROTRON EMISSION MECHANISM IN GAMMA-RAY BURSTS

10^{-6}\lesssim \epsilon_B \lesssim 10^{-3}