Related papers: Does the Geminga, Monogem and PSR J0622+3749 $\gam…
It was suggested that the $\gamma$-ray halo around Geminga might not be interpreted by slow-diffusion. If the ballistic regime of electron/positron propagation is considered, the Geminga halo may be explained even with a large diffusion…
Extended $\gamma$-ray emission has been observed around several nearby pulsars and is commonly interpreted as inverse-Compton radiation produced by relativistic electrons and positrons diffusing in the surrounding interstellar medium. In…
Recently, a few-degrees extended $\gamma$-ray halo in the direction of Geminga pulsar has been detected by HAWC, Milagro and Fermi-LAT. These observations can be interpreted with positrons ($e^+$) and electrons ($e^-$) accelerated by…
The HAWC Collaboration has discovered a $\gamma$-ray emission extended about 2 degrees around the Geminga and Monogem pulsar wind nebulae (PWNe) at $\gamma$-ray energies $E_\gamma >5$ TeV. We analyze, for the first time, almost 10 years of…
The diffusion coefficients around the pulsar $\gamma$-ray halos are highly suppressed compared with the value in the interstellar medium. It is suggested in the literature that the $\gamma$-ray halos can be explained by a…
The HAWC Collaboration has recently reported the detection of bright and spatially extended multi-TeV gamma-ray emission from Geminga, Monogem, and a handful of other nearby, middle-aged pulsars. The angular profile of the emission observed…
Pulsar halos are regions around middle-aged pulsars extending out to tens of parsecs. The large extent of the halos and well-defined central cosmic-ray accelerators make this new class of Galactic sources an ideal laboratory for studying…
Pulsar halos are produced by electrons and positrons diffusing in the interstellar medium around their parent pulsar wind nebulae. Recent observations by HAWC and LHAASO have revealed asymmetric morphologies in the halos surrounding Geminga…
The origin of the positron excess is one of the most intriguing mysteries in astroparticle physics. The recent discovery of extended $\gamma$-ray halos around the pulsars Geminga, Monogem and PSR J0621+3755 have brought indirect evidence…
Extended gamma-ray emission, interpreted as halos formed by the inverse-Compton scattering of ambient photons by electron-positron pairs, is observed toward a number of middle-aged pulsars. The physical origin and actual commonness of the…
The recent HAWC observations of very-high-energy $\gamma$-ray halo around Geminga and Monogem indicate a very slow diffusion of cosmic rays, which results in tiny contribution of positrons from these two pulsars to the local flux. This…
Detailed observation by the High-Altitude Water Cerenkov Observatory of the regions within about 20 pc of the nearby Geminga and PSR B0656+14 pulsars have suggested the need for the diffusion coefficient of 10-100 TeV leptons yielding the…
A novel phenomenon among the recently observed Geminga pulsar halo is the presence of distinct radiation morphology at high energies, while no extended radiation is detected in the 10-500 GeV energy band within a $40\degree\times40\degree$…
Pulsars are factories of relativistic electrons and positrons that propagate away from the pulsar, permeating later our Galaxy. The acceleration and propagation of these particles are a matter of intense debate. In the last few years, we…
Recently, gamma-ray halos of a few degree extension have been detected around two middle-aged pulsars, namely, Geminga and PSR B0656+14, by the High Altitude Water Cherenkov observatory (HAWC). The gamma-ray radiation arise from…
Measuring the electron diffusion coefficient is the most straightforward task in the study of gamma-ray pulsar halos. The updated measurements of the spatial morphology and spectrum of the Geminga halo by the High-Altitude Water Cherenkov…
Numerous extended sources around Galactic pulsars have shown significant $\gamma$-ray emission from GeV to TeV energies, revealing hundreds of TeV energy electrons scattering off of the underlying photon fields through inverse Compton…
Pulsar halos are extended gamma-ray structures generated by electrons and positrons escaping from pulsar wind nebulae (PWNe), considered a new class of gamma-ray sources. They are ideal indicators for cosmic-ray propagation in localized…
Geminga pulsar is surrounded by a multi-TeV $\gamma$-ray halo radiated by the high energy electrons and positrons accelerated by the central pulsar wind nebula (PWN). The angular profile of the $\gamma$-ray emission reported by HAWC…
Pulsar halos (also termed 'TeV halo') are a new class of $\gamma$-ray sources in Galaxy, which manifest as extended $\gamma$-ray emission around middle-age pulsars, as discovered around the Geminga pulsar, the Monogem pulsar and…