The Blast Energy Efficiency of GRBs

Abstract

Using data mostly assembled by previous authors, we consider the linear correlation between the apparent radiative efficiency ${\epsilon }_{\gamma }$ (defined as the ratio of isotropic equivalent radiative output to inferred isotropic equivalent kinetic energy of the blast) and $E_{peak}^{\alpha }$ where $1.4<\alpha <2$, for 17 of 22 GRBs (Lloyd-Ronning and Zhang, 2004). We note in a quantitative manner that this is consistent with the hypothesis that ${\epsilon }_{\gamma }$ and $E_{peak}$ are influenced by viewing angle. We suggest a more general theoretically derived expression for this correlation that could be tested with a richer data set. If the reduction in both ${\epsilon }_{\gamma }$ and $E_{peak}$ is due to viewing angle effects, then the actual radiative efficiency is $\sim 7$. We also find preliminary evidence (with a small sample) for a separate class of weak GRB afterglows.

Submitted to ApJL Feb. 10, 2005

References in corpus (2)

• The Difference Between the Amati and Ghirlanda Relations
• Delayed Afterglow Onset Interpreted as Baryon-Poor Viewing Angle

Cited by in corpus (18)

• Implications of the Early X-Ray Afterglow Light Curves of Swift GRBs
• Spectral-Luminosity relation within individual Fermi GRBs
• The Case for Anisotropic Afterglow Efficiency within Gamma-Ray Burst Jets
• On thermalization in gamma-ray burst jets and the peak energies of photospheric spectra
• The faster the narrower: characteristic bulk velocities and jet opening angles of Gamma Ray Bursts
• A leptonic-hadronic model for the afterglow of gamma-ray burst 090510
• Short and Long GRBs: same emission mechanism?
• The impact of selection biases on the Ep-Liso correlation of Gamma Ray Bursts
• Spectral evolution of Fermi/GBM short Gamma-Ray Bursts
• The High Energy Budget Allocations in Shocks and GRB
• Are Gamma-ray Bursts Universal?
• Spectral Lags Explained as Scattering from Accelerated Scatterers
• Cloaked Gamma Ray Bursts
• A Model for Fast Rising, Slowly Decaying Subpulses in Gamma-Ray Bursts
• Non-thermal high-energy emissions from black holes by a relativistic capillary effect
• Short GRBs Viewed from Far Off Axis
• The energy budget of GRBs based on updated prompt \& afterglow observations
• High Efficiency of Gamma-Ray Bursts Revisited