Related papers: Radiation Hazard of Relativistic Interstellar Flig…
We consider effects on an (ultra-) relativistic jet and its ambient medium caused by high energy cosmic rays accelerated at the jet side boundary. As illustrated by simple models, during the acceleration process a flat cosmic ray…
The space radiation environment is a complex combination of fast-moving ions derived from all atomic species found in the periodic table. The energy spectrum of each ion species varies widely but is prominently in the range of 400 - 600…
A relativistic spacecraft of the type envisioned by the Breakthrough Starshot initiative will inevitably get charged through collisions with interstellar particles and UV photons. Interstellar magnetic fields would, therefore, deflect the…
Plasma containing relativistic particles appears in various forms in the inter galactic medium (IGM): As radio plasma released by active radio galaxies, as fossil radio plasma from former radio galaxies - so called `radio ghosts', as…
Interstellar travel in the Milky Way is commonly thought to be a long and dangerous enterprise, but are all galaxies so hazardous? I introduce the concept of galactic traversability to address this question. Stellar populations are one…
A sudden release of high energy cosmic rays at the centre of a wind sustaining a spiral magnetic field produces cavities of low density and low magnetic field along the axis. The trajectories of high energy cosmic rays are focussed onto the…
Extragalactic relativistic jets are composed by charged particles and magnetic fields, as inferred from the synchrotron emission that we receive from them. The Larmor radii of the particles propagating along the magnetic field are much…
The kinetic effects of magnetic fields on the transport of relativistic jet in the intergalactic medium remain uncertain, especially for their perpendicular component. By particle-in-cell simulations, we find that when only jet electrons…
The collimation and evolution of relativistic outflows in $\gamma$-ray bursts (GRBs) are determined by their interaction with the stellar envelope through which they travel before reaching the much larger distance where the energy is…
Radio maps of AGNs often show linear features, called jets, both on pc as well as kpc scales. These jets supposedly possess relativistic motion and are oriented close to the line of sight of the observer and accordingly the relativistic…
According to the collapsar model, gamma-ray bursts are thought to be produced in shocks that occur after the relativistic jet has broken free from the stellar envelope. If the mass density of the collimated outflow is less than that of the…
Cosmic-ray interactions with interstellar gas and photons produce diffuse gamma-ray emission. In this talk we will review the current understanding of this diffuse emission and its relationship to the problem of the origin of cosmic rays.…
We discuss the possibility that gamma-ray bursts may result from cosmological relativistic blob emitting neutron star jets that precess past the line of sight. Beaming reduces the energy requirements, so that the jet emission can last…
We investigate obstacles of superluminal "warp drive" travels from interactions with interstellar matter and from curvature effects. The effect of collision of interstellar dust particles and photons with the spacecraft will all lead to a…
A field with particularly exciting results over the past few years is the study of the interaction of cosmic rays with interstellar matter. For star formation to take place, gas and dust need to be sufficiently cold for gravity to overcome…
The composition of the astrophysical relativistic jets remains uncertain. By kinetic particle-in-cell simulations, we show that the baryon component in the jet, or the so-called baryon loading effect (BLE), heavily affects relativistic jets…
Cosmic rays are charged energetic particles that permeate the interstellar medium. Their sizeable energy share and penetration power makes them essential players in the dynamical and chemical processes that rule Galactic evolution, such as…
The escape of cosmic rays from the Galaxy is expected to shape their spectrum inside the Galaxy. Yet, this phenomenon is very poorly understood and, in the absence of a physical description, it is usually modelled as free escape from a…
Recently, Hoang et al. (arXiv:1608.05284) reported analysis of the interaction of relativistic spacecrafts with interstellar medium (ISM, i.e. gas atoms and dust particles) relevant for the Breakthrough starshot initiative…
It is shown that a collection of photons with nearly the same frequency exhibits a "condensation" type of phenomenon corresponding to a peak intensity. The observed cosmic background radiation can be explained from this standpoint in terms…