Related papers: Cometary outbursts in the Oort cloud
The motions of comets and neutron stars have been integrated over five billion years in the Galactic potential to determine a gamma-ray burst distribution, presuming that bursts are the result of interactions between these two families of…
In this paper we analyze the dynamical behavior of large dust grains in the vicinity of a cometary nucleus. To this end we consider the gravitational field of the irregularly shaped body, as well as its electric and magnetic fields. Without…
Cometary outgassing can produce torques that change the spin state of the nucleus, influencing the evolution and lifetimes of comets (1,2). If these torques spin up the rotation to the point that centripetal forces exceed the material…
Kuiper-like belts of planetesimals orbiting stars other than the Sun are most commonly detected from the thermal emission of small dust produced in collisions. Emission from gas, most notably CO, highlights the cometary nature of these…
Star formation feedback can drive large-scale, multi-phase galactic outflows. The dynamical and thermodynamical interaction between the hot and cooler phases is a prime focus of both observational and theoretical work. Here, we analyze…
Recent results from a multiwavelength survey of spatially resolved outflows in nearby active galaxies are presented. Optical Fabry-Perot and long-slit spectroscopic data are combined with VLA and ROSAT images, when available, to probe the…
Hydrodynamical simulations of jets interacting with clouds moving in the ambient medium of the host galaxy are presented. Clouds with sizes of the order of the jet diameter and smaller, crossing the path of the jet with different speeds are…
Outbursts are known to begin with a sudden appearance and steep brightening of a "stellar nucleus" --- an unresolved image of a plume of material on its way from the comet's surface and an initial stage of an expanding halo of ejecta. Since…
The observed correlation between global low cloud amount and the flux of high energy cosmic rays supports the idea that ionization plays a crucial role in tropospheric cloud formation. We explore this idea quantitatively with a simple model…
We investigate whether the swirling cold front in the core of the Perseus Cluster of galaxies has affected the outer buoyant bubbles that originated from jets from the Active Galactic Nucleus in the central galaxy NGC1275. The inner bubbles…
This paper deals with the cosmic-ray penetration into molecular clouds and with the related gamma--ray emission. High energy cosmic rays interact with the dense gas and produce neutral pions which in turn decay into two gamma rays. This…
The innermost parts of powerful jets in active galactic nuclei are surrounded by dense, high-velocity clouds from the broad-line region, which may penetrate into the jet and lead to the formation of a strong shock. Such jet-cloud…
A number of observations have revealed atomic and/or molecular lines in active galaxies hosting jets and outflows. Line widths indicate outward motions of hundreds to few thousands of kilometers per second. They appear associated to the…
Significant nonradial, nongravitational accelerations with magnitudes incompatible with radiation-driven effects have been reported in seven small, photometrically inactive near-Earth objects. Two of these objects exhibit large transverse…
Every Galactic environment is characterized by a stellar density and a velocity dispersion. With this information from literature, we simulated flyby encounters for several Galactic regions, numerically calculating stellar trajectories as…
The high rate of star formation and supernova explosions of starburst galaxies make them interesting sources of high energy radiation. Depending upon the level of turbulence present in their interstellar medium, the bulk of cosmic rays…
Milgromian dynamics (MD or MOND) is a promising physical description excelling especially in galaxies. When formulated as a modified gravity theory, it leads to the so called external field effect (EFE). In the case of the solar system this…
Young stars are associated with prominent outflows of molecular gas. The ejection of gas via these outflows is believed to remove angular momentum from the protostellar system, thus permitting young stars to grow by accretion of material…
We report the results of a series of AMR radiation-hydrodynamic simulations of the collapse of massive star forming clouds using the ORION code. These simulations are the first to include the feedback effects protostellar outflows, as well…
The Centaurs are recent escapees from the Kuiper belt that are destined either to meet fiery oblivion in the hot inner regions of the Solar system or to be ejected to the interstellar medium by gravitational scattering from the giant…