Related papers: Multifrequency Behaviour of Galactic and Extragala…
The spectroscopic development of classical novae is described as a narrative of the various stages of the outburst. The review highlights the multiwavelength aspects of the phenomenology and the recent developments related to structure,…
A brief summary of some highlights in the study of high energy astrophysical sources over the past decade is presented. It is argued that the great progress that has been made derives largely from the application of new technology to…
Astrophysical explosions result from the release of magnetic, gravitational, or thermonuclear energy on dynamical timescales, typically the sound-crossing time for the system. These explosions include solar and stellar flares, eruptive…
Multi-wavelength studies at radio, infrared, optical, X-ray, and TeV wavelengths have discovered probable counterparts to many Galactic sources of GeV emission detected by EGRET. These include pulsar wind nebulae, high mass X-ray binaries,…
The discovery of GeV gamma-rays from classical novae has led to a reassessment of these garden-variety explosions, and highlighted their importance for understanding radiative shocks, particle acceleration, and dust formation in more…
The physical mechanism driving mass ejection during a nova eruption is still poorly understood. Possibilities include ejection in a single ballistic event, a common envelope interaction, a continuous wind, or some combination of these…
Multiwavelength radiation from relativistic particles accelerated at shocks in novae and other astrophysical sources carries a wealth of information about the outflow properties and the microphysical processes at work near the shocks. The…
Classical novae are the most common astrophysical thermonuclear explosions, occurring on the surfaces of white dwarf stars accreting gas from companions in binary star systems. Novae typically expel ~10^(-4) solar masses of material at…
The discovery of novae as sources of ~GeV gamma-rays highlights the key role of shocks and relativistic particle acceleration in these transient systems. Although there is evidence for a spectral cut-off above energies ~1-100 GeV at…
Astronomy at the highest energies observed must be performed by studying neutrinos rather than photons because the universe is opaque to photons of these energies. By making observations of neutrinos with energies above 10 EeV one can…
Gamma-ray astronomy explores the most energetic photons in nature to address some of the most pressing puzzles in contemporary astrophysics. It encompasses a wide range of objects and phenomena: stars, supernovae, novae, neutron stars,…
The development of techniques whereby gamma rays of energy 100 GeV and above can be studied from the ground, using indirect, but sensitive, techniques has opened up a new area of high energy photon astronomy. The most exciting result that…
Gamma ray bursts (GRBs) are astronomical phenomena detected at highest energies. The gamma ray photons carry energies on the order of mega-electronovolts and arrive to us from the point-like sources that are uniformly distributed on the…
Novae are the observable outcome of a transient thermonuclear runaway on the surface of an accreting white dwarf in a close binary system. Their high peak luminosity renders them visible in galaxies out beyond the distance of the Virgo…
Novae have long been expected to be sources of emission at several MeV from the decay of radioactive elements in the novae ejecta, however, they were not anticipated to be sources of continuum emission in the GeV energy domain. In March…
Context. In the last five years the Fermi Large Area Telescope (LAT) instrument detected GeV {\gamma}-ray emission from five novae. The GeV emission can be interpreted in terms of an inverse Compton process of electrons accelerated in a…
Despite being one of the longest known classes of astrophysical transients, novae continue to present modern surprises. The Fermi-LAT discovered that many if not all novae are GeV gamma ray sources, even though theoretical models had not…
We report serendipitous discovery of three new dwarf novae which eruptions in 2010 were observed by the ongoing microlensing survey OGLE-IV. All three objects are located in the Galactic bulge fields observed with the highest cadence of 20…
Infrared interferometric observations have a great deal of potential to unravel the nature of the nova eruptions. We suggest that techniques, already in place, to derive the ejection details at optical wavelengths be used with infrared…
Ultra high energy cosmic ray events presently show a spectrum, which we interpret here as galactic cosmic rays due to a starburst in the radio galaxy Cen A pushed up in energy by the shock of a relativistic jet. The knee feature and the…