480 citations · 6k across the 156 of their papers we have counts for
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Towards Resolving the Crab Problem: A Linear Accelerator?
Ioannis Contopoulos, Demosthenes Kazanas
Using the exact solution of the axisymmetric pulsar magnetosphere derived in a previous publication and the conservation laws of the associated MHD flow, we show that the Lorentz f…
Cosmic Rays and Large Extra Dimensions
D. Kazanas, A. Nicolaidis
We have proposed that the cosmic ray spectrum "knee", the steepening of the cosmic ray spectrum at energy $E \gsim 10^{15.5}$ eV, is due to "new physics", namely new interactions a…
On time-dependent X-ray reflection by photoionized accretion disks: implication for Fe K-alpha line reverberation studies of AGN
Sergei Nayakshin, Demos Kazanas
We perform a first study of time-dependent X-ray reflection in photo-ionized accretion disks. We assume a step-functional change in the X-ray flux and use a simplified prescription…
Frequency-dependent time lags in the X-ray emission of the Seyfert galaxy NGC 7469
I. E. Papadakis, K. Nandra, D. Kazanas
We report the discovery of time lags in the cross-spectra of the X-ray light curves of the Seyfert galaxy NGC 7469. This behavior is common in Galactic black hole and neutron star…
Narrow Moving Fe K-alpha lines from magnetic flares in AGN
Sergei Nayakshin, Demosthenes Kazanas
We point out that luminous magnetic flares, thought to occur in standard AGN accretion disks, cannot be located much higher than few pressure scale heights above the disk. Using th…
Exact Expressions for the Critical Mach Numbers in the Two-Fluid Model of Cosmic-Ray Modified Shocks
Peter A. Becker, Demosthenes Kazanas
The acceleration of relativistic particles due to repeated scattering across a shock wave remains the most attractive model for the production of energetic cosmic rays. This proces…