7 papers
Radiative Efficiencies of Continuously Powered Blast Waves
Ehud Cohen, Tsvi Piran
We use general arguments to show that a continuously powered radiative blast wave can behave self similarly if the energy injection and radiation mechanisms are self similar. In th…
Fluid dynamics of partially radiative blast waves
Ehud Cohen, Tsvi Piran, Re'em Sari
We derive a self similar solution for the propagation of an extreme relativistic (or Newtonian) radiative spherical blast wave into a surrounding cold medium. The solution is obtai…
The Hardness Distribution of Gamma-Ray Bursts
Ehud Cohen, Tsvi Piran, Ramesh Narayan
It is often stated that gamma-ray bursts (GRBs) have typical energies of several hundreds $\keV$, where the typical energy may be characterized by the hardness H, the photon energy…
The Implications of Direct Red-Shift Measurement of -ray Bursts
Ehud Cohen, Tsvi Piran
The recent discoveries of X-ray and optical counterparts for GRBs, and a possible discovery of a host galaxy, implies that a direct measurement of the red-shift of some GRBs host g…
Possible Evidence for Relativistic Shocks in Gamma-Ray Bursts
E. Cohen, J. I. Katz, T. Piran +3
Relativistic shock models of gamma-ray bursts may be tested by comparison of their predicted low energy asymptotic spectral indices s to observations. Synchrotron radiation theory…
A Simultaneous Spectral Invariant Analysis of the GRB Count Distribution and Time Dilation
Ehud Cohen, Tsvi Piran
The analysis of the BATSE's count distribution within cosmological models suffers from observational uncertainties due to the variability of the bursts' spectra: when BATSE observe…