Dynamical Oscillations and Glitches in AXPs (2009)
Eichler, David, Shaisultanov, Rashid
It is suggested that dynamical oscillations of magnetars trigger vortex unpinning and attendant glitches. Depending on the energy release, the glitch may be accompanied by an X-ray heating event. A...
Spectral Lags Explained as Scattering from Accelerated Scatterers (2008)
A quantitative theory of spectral lags for $\gamma$-ray bursts (GRBs) is given. The underlying hypothesis is that GRB subpulses are photons that are scattered into our line of sight by local...
A Universal Central Engine Hypothesis for Short and Long GRBs (2008)
Eichler, David, Guetta, Dafne, Manis, Hadar
It is noted that X-ray tails (XRTs) of short, hard $\gamma$-ray bursts (SHBs) are similar to X-ray flashes (XRFs). We suggest a universal central engine hypothesis, as a way of accounting for this...
A Model for Fast Rising, Slowly Decaying Subpulses in Gamma-Ray Bursts (2007)
Gamma ray bursts (GRB's) often feature subpulses that have a distinctively asymmetric profile -- they rise quickly and decay much more slowly, while their spectrum softens slightly with observer...
On the corona of magnetars (2007)
Lyubarsky, Yury, Eichler, David
Slow dissipation of non-potential magnetic fields in the magnetosphere of the magnetar is assumed to accelerate particles to hundreds MeV along the magnetic field lines. We consider interaction of...
When Do Ultra-relativistic Shocks Make Energetic Particle Populations? (2006)
Eichler, David, Ellison, Donald C.
This paper has been withdrawn by the authors due to missing references to earlier work and an error in the interpretation of Figures 2 and 3. A corrected version is in preparation.
Long Term Cooling of Magnetar Crusts (2006)
Eichler, David, Lyubarsky, Yuri, Kouveliotou, Chryssa, Wilson, Colleen A.
X-ray emission following giant flares of magnetars can be categorized into three categories of time scales (a) short term afterglow (b) medium term afterglow and (c) long term afterglow. Short term...
Are Gamma-ray Bursts Universal? (2006)
Eichler, David, Levinson, Amir
It is noted that the Liang-Zhang correlation can be accounted for with the viewing angle interpretation proposed earlier. The Ghirlanda correlation, recently generalized by Nava et al (2006) to a...
Are GRB shocks mediated by the Weibel instability? (2005)
Lyubarsky, Yuri, Eichler, David
It is estimated that the Weibel instability is not generally an effective mechanism for generating ultrarelativistic astrophysical shocks. Even if the upstream magnetic field is as low as in the...
The Case for Anisotropic Afterglow Efficiency within Gamma-Ray Burst Jets (2005)
Eichler, David, Granot, Jonathan
Early X-ray afterglows recently detected by {\it Swift} frequently show a phase of very shallow flux decay lasting from $\sim 10^{2.5} $s up to $\sim 10^4 $s, followed by a steeper, more familiar...
Ultrahigh Energy Activity in Giant Magnetar Outbursts (2005)
The recent superflare of 27 December 2004 from the magnetar SGR 1806-20 was the brightest extrasolar flash ever recorded in the modern era. The chances for seeing exotic ultrahigh energy (UHE)...
The Difference Between the Amati and Ghirlanda Relations (2005)
Levinson, Amir, Eichler, David
It is pointed out that the beaming correction commonly inferred from the achromatic breaks in the afterglow light curve is biased in situations where the isotropic equivalent energy is affected by...
Delayed Afterglow Onset Interpreted as Baryon-Poor Viewing Angle (2005)
We have suggested previously that baryons in GRB fireballs infiltrate from the surrounding walls that collimate the fireball. The efficiency $\epsilon_b$ for generating blast energy can then be angle...
Ongoing Space Physics - Astrophysics Connections (2005)
I review several ongoing connections between space physics and astrophysics: a) Measurements of energetic particle spectra have confirmed theoretical prediction of the highest energy to which shocks...
The efficiency of electron acceleration in collisionless shocks and GRB energetics (2005)
Afterglow observations are commonly used to determine the parameters of GRB explosions, the energy E, surrounding density n, post-shock magnetic field equipartition fraction \epsilon_B and electron...
Galactic Positrons From Localized Sources (2005)
The anomalous bump in the cosmic ray positron to electron ratio at $10 GeV$ can be explained as being a component from a point source that was originally harder than the primary electron background...
An Interpretation of the $h\nu_{peak}$ - $E_{iso}$ Correlation for GRB (2004)
Eichler, David, Levinson, Amir
The $h\nu_{peak}/100 KeV \sim [E_{iso}/10^{52} \rm{erg}]^{1/2}$ correlation reported recently by Amati et al. (2002) and Lamb et al. (2003) for long GRB's can be interpreted as a viewing angle effect...
A braneworld puzzle about entropy bounds and a maximal temperature (2004)
Brustein, Ram, Eichler, David, Foffa, Stefano
Entropy bounds applied to a system of N species of light quantum fields in thermal equilibrium at temperature T are saturated in four dimensions at a maximal temperature T_max=M_Planck/N^1/2. We show...
Levinson, Amir, Eichler, David
The polarization of gamma ray emission scattered off the baryon rich material that collimates a GRB fireball and the coasting speed of the irradiated matter are calculated numerically for different...
Photon Pickup by Intense Poynting Flows (2003)
It is suggested that a Poynting flux-dominated outflow with a sufficiently strong magnetic field can pick up hard X-ray photons when the magnetic field is of sufficient strength. The zeroth...
Compton Sailing and Strong Polarization (2003)
It is noted that a surface layer of matter in contact with a sufficiently super-Eddington, radially combed photon flux typically attains a relativistic coasting state whereby the radiation does not...
Polarization of GRB via scattering off a relativistic sheath (2003)
Eichler, David, Levinson, Amir
GRB fireballs could be ensheathed by a relativistic, baryon-enriched outflow that would in selected directions scatter a polarized beam of gamma rays. The strong polarization recently announced by...
Ultrahigh Energy Neutrals from Extreme Magnetic Flares (2003)
It is shown that bulk acceleration during reconnection of extremely strong magnetic fields near compact objects can accelerate ions to Lorentz factors of $\sim 10^2 \sigma^{3/5}$ under general...
Waiting for the Big One: A New Class of SGR Outbursts? (2002)
It is suggested that magnetars eventually become unstable to a dynamic overturning instability that destroys most of their dipole moment in a single event. It is further suggested that such an...
The X-ray jet in the Crab Nebula: radical implications for pulsar theory? (2002)
Lyubarsky, Yury, Eichler, David
The recent Chandra image of the Crab nebula shows a striking, axisymmetric polar jet. It is shown that jets are formed in axisymmetric, magnetized pulsar winds and that the jet luminosity scales...
Optical SETI with Air Cerenkov Telescopes (2001)
Eichler, David, Beskin, Gregory
We propose using large Air Cerenkov Telescopes (ACT's) to search for optical, pulsed signals from extra-terrestrial intelligence. Such dishes collect tens of photons from a nanosecond-scale pulse of...
Probing the Planck Scale with Neutrino Oscillations (2001)
Brustein, Ram, Eichler, David, Foffa, Stefano
Quantum gravity "foam", among its various generic Lorentz non-invariant effects, would cause neutrino mixing. It is shown here that, if the foam is manifested as a nonrenormalizable effect at scale...
Gaseous Disks of Spiral Galaxies: Arms and Rings (2000)
Liverts, Edward, Griv, Evgeny, Gedalin, Michael, Eichler, David, Yuan, Chi
An improved linear stability theory of small-amplitude oscillations of a self-gravitating, infinitesimally thin gaseous disk of spiral galaxies has been developed. It was shown that in the...
Supercomputer Simulations of Disk Galaxies (2000)
Griv, Evgeny, Gedalin, Michael, Liverts, Edward, Eichler, David, Kimhi, Yehoshua
The time evolution of models for an isolated disk of highly flattened galaxies of stars is investigated by direct integration of the Newtonian equations of motion of N=30,000 identical stars over a...
Griv, Evgeny, Gedalin, Michael, Liverts, Edward, Eichler, David, Yuan, Chi
The kinetic theory is used to study the evolution of the self-gravitating disk of planetesimals. The effects of frequent collisions between planetesimals are taken into account by using a Krook...
Griv, Evgeny, Gedalin, Michael, Eichler, David, Yuan, Chi
Linear theory is used to determine the stability of the self-gravitating, rapidly (and nonuniformly) rotating, two-dimensional, and collisional particulate disk against small-amplitude gravity...
Weakly nonlinear theory of the Jeans instability in disk galaxies of stars (2000)
Griv, Evgeny, Gedalin, Michael, Eichler, David, Yuan, Chi
The reaction of collective oscillations excited in the interaction between aperiodically growing Jeans-type gravity perturbations and stars of a rapidly rotating disk of flat galaxies is considered....
Particle modeling of disk-shaped galaxies of stars on nowadays concurrent supercomputers (2000)
Griv, Evgeny, Gedalin, Michael, Liverts, Edward, Eichler, David, Kimhi, Yehoshua, Yuan, Chi
The time evolution of initially balanced, rapidly rotating models for an isolated disk of highly flattened galaxies of stars is calculated. The method of direct integration of the Newtonian equations...
The Shortest Scale of Quantum Field Theory (2000)
Brustein, Ram, Eichler, David, Foffa, Stefano, Oaknin, David H.
It is suggested that the Minkowski vacuum of quantum field theories of a large number of fields N would be gravitationally unstable due to strong vacuum energy fluctuations unless an N dependent...
On "box" models of shock acceleration and electron synchrotron spectra (1999)
Drury, Luke O'C, Duffy, Peter, Eichler, David, Mastichiadis, Apostolos
The recent detection of high energy gamma-rays coming from supernova remnants and active galactic nuclei has revived interest in the diffusive shock acceleration of electrons. In the present paper we...
Planck Scale Mixing and Neutrino Puzzles (1998)
Eichler, David, Seidov, Zakir F.
It is hypotesized that neutrinos are massles and mixed among three (muon, electron and tau) flavors with a mixing length proportional to (E_nu/E_Planck)^-2. It is suggested that this hypothesis...
Radiation Dosimetry of Binary Pulsars (1995)
Eichler, David, Nath, Biman B.
Companion stars exposed to high energy radiation from a primary neutron star or accreting black hole can experience significant spallation of their heavy elements, so that their atmospheres would be...
A Possible Forest of Emission Lines from Proto-galaxies (1993)
The possibility of detecting proto-galaxies in the UV band is pointed out, assuming that galaxy formation occured at z $\sim 5-6$. It is shown that the diffuse gas in collapsing galaxy sized objects...