Related papers: Gammaless GRBs?
I summarize recent results about how a neutron star binary coalescence can produce short gamma-ray bursts (GRBs). Two possibilities are discussed: the annihilation of neutrino anti-neutrino pairs above the merged remnant and the exponential…
It is generally believed that cosmological Gamma Ray Bursts (GRBs) are produced by the deceleration of relativistic objects with Lorentz factor (Gamma) >~ 100. We study the possibility that some GRBs are produced along with relativistic…
If the threshold for $e^{-}e^{+}$ pair production depends on an angle between photon momenta, and if the $\gamma$-rays are collimated right in gamma-ray burst (GRB) source then another solution of the compactness problem is possible. The…
Very high energy, short wavelength, neutrinos may interact with the space-time foam predicted by theories of quantum gravity. They would propagate like light through a crystal lattice and be delayed, with the delay depending on the energy.…
Gamma-ray bursts (GRBs) are powered by ultra-relativistic jets. Usually a minimum value of the Lorentz factor of the relativistic bulk motion is obtained based on the argument that the observed high energy photons ($\gg {\rm MeV}$) can…
Gamma-ray bursts (GRBs) are the most luminous electromagnetic burst in the Universe. They occur when a rapidly rotating massive star collapses or a binary neutron star merges. These events leave a newborn central compact object, either a…
Gamma-Ray Bursts (GRBs) have been proposed as a leading candidate for acceleration of ultra high-energy cosmic rays, which would be accompanied by emission of TeV neutrinos produced in proton-photon interactions during acceleration in the…
A $\gamma$-ray source must have a limited optical depth to pair production. This simple condition, called compactness, implies that gamma-ray bursts (GRBs) must involve a highly relativistic motion ($\Gamma \gtrsim 100$) giving the first…
We exploit the fact that General Theory of Relativity (GTR) predicts the existence of compact objects having surface gravitational redshift z_s < =z_c=0.615 when the Equation of State (EOS) has the stringest general constraint that the…
Long-duration gamma-ray bursts (GRBs) have been often considered as the natural evolution of some core-collapse supernovae (SNe). While GRBs with relativistic jets emit an electromagnetic signal, GRBs with mildly relativistic jets are…
Gamma ray bursts (GRBs) are the most luminous physical phenomena in the universe. The relativistic effect on the blast wave associated with the GRB introduces the gamma factor. Here we put an upper limit on the gamma factor via constraints…
In this contribution we briefly introduce a mechanism for short gamma ray burst emission different from the usually assumed compact object binary merger progenitor model. It is based on the energy release in the central regions of neutron…
I argue that cosmic Gamma-ray Bursts (GRB) may be produced by collapses or mergers of stars made of `mirror' matter. The mirror neutrinos (which are sterile for our matter) produced at these events can oscillate into ordinary neutrinos. The…
Gamma-Ray Bursts (GRBs) are the brightest objects observed. They are also the most relativistic objects known so far. GRBs occur when an ultrarelativisitic ejecta is slowed down by internal shocks within the flow. Relativistic particles…
If the ordinary neutrinos oscillate into a sterile flavor in a manner consistent with the Super-Kamiokande data on the zenith-angle dependence of atmospheric mu-neutrino flux, an energy sufficient to power a typical cosmic gamma-ray burst…
Lorentz Invariance Violation (LIV) arises in various quantum-gravity theories. As the typical energy for quantum gravity is the Planck mass, $M_{pl}$, LIV will, most likely, be manifested at very high energies that are not accessible on…
Knowledge of the bulk Lorentz factor $\Gamma_{0}$ of GRBs allows us to compute their comoving frame properties shedding light on their physics. Upon collisions with the circumburst matter, the fireball of a GRB starts to decelerate,…
Typical observational gamma-ray burst (GRB) spectra are discussed and, in this connection, what is the origin of the compactness problem and how it was solved at first. If the threshold for $e^{-}e^{+}$ pair production depends on an angle…
Gamma-ray bursts (GRBs) are a mixed class of sources consisting of, at least, the long duration and short-hard subclasses, the X-ray flashes, and the low-luminosity GRBs. In all cases, the release of enormous amounts of energy on a short…
It is proposed that the gamma ray burst photons near the peak of the spectrum at several hundred KeV are produced on very compact scales, where photon production is limited by blackbody effects and/or the requirement of energetic quanta…