648 citations · 7.8k across the 137 of their papers we have counts for
46 papers · 1 filter
Dark Matter Signatures in the Anisotropic Radio Sky
Le Zhang, Guenter Sigl
We calculate intensity and angular power spectrum of the cosmological background of synchrotron emission from cold dark matter annihilations into electron positron pairs. We compar…
Lorentz Violation and Ultrahigh-Energy Photons
Matteo Galaverni, Guenter Sigl
The propagation of photons, electrons and positrons at ultra-high energies above 10^{19} eV can be changed considerably if the dispersion relations of these particles are modified…
Time Structure of Ultra-High Energy Cosmic Ray Sources and Consequences for Multi-messenger Signatures
Guenter Sigl
The latest results on the sky distribution of ultra-high energy cosmic ray sources have consequences for their nature and time structure. If the sources accelerate predominantly nu…
Ultrahigh energy cosmic rays as heavy nuclei from cluster accretion shocks
Susumu Inoue, Guenter Sigl, Francesco Miniati +1
Large-scale accretion shocks around massive clusters of galaxies, generically expected in hierarchical scenarios of cosmological structure formation, are shown to be potential sour…
Effects of Axion-Photon Mixing on Gamma-Ray Spectra from Magnetized Astrophysical Sources
Kathrin A. Hochmuth, Guenter Sigl
Astrophysical gamma-ray sources come in a variety of sizes and magnetizations. We deduce general conditions under which gamma-ray spectra from such sources would be significantly a…
Ultra High Energy Cosmic ray and gamma-ray signatures of inductive acceleration in AGN jets
Rachid Ouyed, Guenter Sigl, Maxim Lyutikov
The highest energy cosmic rays could be produced by drifts in magnetized, cylindrically collimated, sheared jets of powerful active galaxies (i.e. FR II radiogalaxies; radio loud q…
Ultra-High Energy Cosmic Rays and the GeV-TeV Diffuse Gamma-Ray Flux
Oleg E. Kalashev, Dmitry V. Semikoz, Guenter Sigl
Ultra-high energy cosmic ray protons accelerated in astrophysical objects produce secondary electromagnetic cascades during propagation in the cosmic microwave and infrared backgro…
Non-Universal Spectra of Ultra-High Energy Cosmic Ray Primaries and Secondaries in a Structured Universe
Guenter Sigl
Analytical calculations of extra-galactic cosmic ray spectra above ~10^17 eV are often performed assuming continuous source distributions, giving rise to spectra that depend little…
Ultrahigh energy cosmic rays as heavy nuclei from cluster accretion shocks
Susumu Inoue, Guenter Sigl, Francesco Miniati +1
Large-scale accretion shocks around massive clusters of galaxies, generically expected in the cold dark matter scenario of cosmological structure formation, are shown to be plausib…
High Energy Astroparticle Physics
Guenter Sigl
We give a brief (and highly incomplete) overview of the current experimental and theoretical status of high energy cosmic rays and their secondary gamma-rays and neutrinos. We focu…
Gravitational-wave background from compact objects embedded in AGN accretion disks
Guenter Sigl, Jeremy Schnittman, Alessandra Buonanno
We consider a model in which massive stars form in a self-gravitating accretion disk around an active galactic nucleus (AGN). These stars may evolve and collapse to form compact ob…
Ultra High Energy Cosmic Radiation: Experimental and Theoretical Status
Guenter Sigl
We give a brief overview of the current experimental and theoretical status of cosmic rays above ~10**17 eV. We focus on the role of large scale magnetic fields and on multi-messen…
Gravitational Waves from Compact Objects Accreting onto Active Galactic Nuclei
Jeremy D. Schnittman, Guenter Sigl, Alessandra Buonanno
We consider a model in which massive stars form in a self-gravitating accretion disk around an active galactic nucleus. These stars may evolve and collapse to form compact objects…
Cosmological Gravitational Wave Background from Phase Transitions in Neutron Stars
Guenter Sigl
It has recently been suggested that collapse of neutron stars induced by a phase transition to quark matter can be a considerable source of gravitational waves with kHz frequencies…
Gamma Ray Astronomy with Magnetized Zevatrons
Eric Armengaud, Guenter Sigl, Francesco Miniati
Nearby sources of cosmic rays up to a ZeV(=10^21 eV) could be observed with a multi-messenger approach including secondary gamma-rays and neutrinos. If cosmic rays above ~10^18 eV…
Magnetized Sources of Ultra-high Energy Nuclei and Extragalactic Origin of the Ankle
Guenter Sigl, Eric Armengaud
It has recently been suggested that ultra-high energy cosmic rays could have an extragalactic origin down to the "second knee" at ~4x10^{17}eV. In this case the "ankle" or "dip" at…
Ultrahigh Energy Nuclei Propagation in a Structured, Magnetized Universe
Eric Armengaud, Guenter Sigl, Francesco Miniati
We compare the propagation of iron and proton nuclei above 10^19 eV in a structured Universe with source and magnetic field distributions obtained from a large scale structure simu…
Cosmic Magnetic Fields and Their Influence on Ultra-High Energy Cosmic Ray Propagation
Guenter Sigl, Francesco Miniati, Torsten Ensslin
We discuss the influence of large scale cosmic magnetic fields on the propagation of hadronic cosmic rays above 10^19 eV based on large scale structure simulations. Our simulations…
Ultra-High Energy Cosmic Ray Nuclei from Individual Magnetized Sources
Guenter Sigl
We investigate the dependence of composition, spectrum and angular distributions of ultra-high energy cosmic rays above 10^19 eV from individual sources on their magnetization. We…
Some Current Theoretical Issues around Ultra-High Energy Cosmic Rays
Guenter Sigl
We address some current theoretical issues around ultra-high energy cosmic rays. We recall that scenarios producing more gamma-rays than cosmic rays up to high redshift can in gene…
Ultra-High Energy Cosmic Ray Probes of Large Scale Structure and Magnetic Fields
Guenter Sigl, Francesco Miniati, Torsten Ensslin
We study signatures of a structured universe in the multi-pole moments, auto-correlation function, and cluster statistics of ultra-high energy cosmic rays above 10^19 eV. We compar…
Ultra-High Energy Cosmic Rays from Quasar Remnants
C. Isola, G. Sigl, G. Bertone
One of the models recently proposed to explain the origin of the ultra high energy cosmic rays assumes that these particles may be accelerated by the electromotive force around pre…
Signatures of Magnetized Large Scale Structure in Ultra-High Energy Cosmic Rays
Guenter Sigl, Francesco Miniati, Torsten Ensslin
We investigate the impact of a structured universe in the multi-pole moments, auto-correlation function, and cluster statistics of cosmic rays above 10^19 eV. We compare structured…
Gravitational Effects on Particle Dark Matter and Indirect Detection
Guenter Sigl, Gianfranco Bertone
The annihilation signal of particle dark matter can be strongly enhanced in over-dense regions such as close to the Galactic centre. We summarize some of our recent results on flux…