Related papers: Gamma Ray Pulsars: Observations
In this article, we revisit the gamma-ray emission observed from millisecond pulsars and globular clusters. Based on 5.6 years of data from the Fermi Gamma-Ray Space Telescope, we report gamma-ray spectra for 61 millisecond pulsars, finding…
There is active interest in the extent to which unresolved gamma-ray pulsars contribute to the galactic diffuse emission, and whether unresolved gamma-ray pulsars could be responsible for the excess of diffuse galactic emission above 1 GeV…
The fast temporal structures and cosmological distances of gamma-ray bursts (GRBs) afford a natural laboratory for testing theories of frequency-dependent propagation of high-energy photons, as predicted for quantum gravity (QG). We…
The pulsar light curves and energy spectra are explored in dissipative pulsar magnetospheres with the Aristotelian electrodynamics (AE), where particle acceleration is fully balanced with radiation reaction. The AE magnetospheres with…
A population of unidentified gamma-ray sources is forming a structure resembling a halo around the Galactic center. These sources are highly variable, and hence they should be associated with compact objects. Microquasars are objects…
For about two decades, a population of relative small and nearby molecular clouds has been known to exist at high Galactic latitudes. Lying more than 10$^\circ$ from the Galactic plane, these clouds have typical distances of $\sim$150 pc,…
Recent results from the PAMELA satellite indicate the presence of a large flux of positrons (relative to electrons) in the cosmic ray spectrum between approximately 10 and 100 GeV. As annihilating dark matter particles in many models are…
Recent measurements of the Geminga and B0656+14 pulsars by the gamma-ray telescope HAWC (along with earlier measurements by Milagro) indicate that these objects generate significant fluxes of very high-energy electrons. In this paper, we…
The Large Area Telescope (LAT) on board the Fermi satellite has detected ~120 pulsars above 100 MeV. While most gamma-ray pulsars have spectra that are well modeled by a power law with an exponential cut-off at around a few GeV, some show…
Over the past few decades impressive progress has been made in the field of photon polarimetry, especially in the hard X-ray and soft gamma-ray energy regime. Measurements of the linear degree of polarization for some of the most energetic…
The search for gamma radiation in clusters of galaxies represents a precious tool to investigate the history of these large scale structures. Clusters or sources within them accelerate cosmic rays, as demonstrated by the detection of radio…
Being the most extreme explosions in the universe, gamma-ray bursts (GRBs) provide a unique laboratory to study various plasma physics phenomena. The complex lightcurve and broad-band, non-thermal spectra indicate a very complicated system…
We report on the likely detection of pulsed high-energy gamma-rays from the binary millisecond pulsar PSR J0218+4232 in 100-1000 MeV data from CGRO EGRET. Imaging analysis demonstrates that the highly significant gamma-ray source 2EG…
After initial claims and a long hiatus, it is now established that several binary stars emit high (0.1-100 GeV) and very high energy (>100 GeV) gamma rays. A new class has emerged called 'gamma-ray binaries', since most of their radiated…
High energy gamma-ray astronomy has recently made significant progresss through ground-based instruments like the {\it H.E.S.S.} array of imaging atmospheric Cherenkov telescopes. The unprecedented angular resolution and the large field of…
The AGILE gamma-ray satellite provides large sky exposure levels ($\geq 10^9$ cm$^2$ s per year on the Galactic Plane) with sensitivity peaking at $E\sim$100 MeV where the bulk of pulsar energy output is typically released. Its $\sim$1…
We study the gamma-ray emissions from an outer-magnetospheric potential gap around a rotating neutron star. Migratory electrons and positrons are accelerated by the electric field in the gap to radiate copious gamma-rays via curvature…
The high-quality Fermi LAT observations of gamma-ray pulsars have opened a new window to understanding the generation mechanisms of high-energy emission from these systems. The high statistics allow for careful modeling of the light curve…
The Large Area Telescope (LAT), Fermi's main instrument, is providing a new view of the local energetic pulsar population. In addition to identifying a pulsar origin of a large fraction of the bright unidentified Galactic EGRET sources, the…
Ultra-high energy cosmic ray protons accelerated in astrophysical objects produce secondary electromagnetic cascades during propagation in the cosmic microwave and infrared backgrounds. We show that such cascades can contribute between ~1%…