Related papers: Geminga's pulsar halo: an X-ray view
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…
Geminga is a nearby (250 pc) middle-aged (spin-down time scale ~12,000 years) pulsar associated with a supernova remnant. Geminga has been a prime candidate for the origin of the unexpectedly high flux of cosmic-ray positrons above 10 GeV…
The recent detection of extended $\gamma$-ray emission around middle-aged pulsars is interpreted as inverse-Compton scattering of ambient photons by electron-positron pairs escaping the pulsar wind nebula, which are confined near the system…
Extended regions of very high energy $\gamma$-ray emission associated with middle-aged pulsars have been found by $\gamma$-ray observatories. These regions, called TeV halos or pulsar halos, are thought to be created when energetic…
The Geminga pulsar, one of the brighest gamma-ray sources, is a promising candidate for emission of very-high-energy (VHE > 100 GeV) pulsed gamma rays. Also, detection of a large nebula have been claimed by water Cherenkov instruments. We…
TeV Halos, extended regions of TeV gamma-ray emission around middle-aged pulsars, have recently been established as a new source class in gamma-ray astronomy. These halos have been attributed to relativistic electrons and positrons that…
The recent detection of the Geminga PWN by HAWC in the multi-TeV band allows us to infer precious information about the transport of pairs in the immediate surroundings of the pulsar and on the spectrum of pairs contributed by a…
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…
Pulsars convert a significant fraction of their total spin-down power into very high-energy electrons, leading to the formation of TeV halos. It is not yet known, however, whether these sources also efficiently accelerate electrons at lower…
The Geminga gamma ray source was first detected by the SAS-2 gamma-ray satellite observatory and the COS-B x-ray satellite observatory, and has been identified as a radio-quiet pulsar associated with a 300,000 year old supernova remnant.…
Using data from the HAWC gamma-ray Telescope, we have studied a sample of 37 millisecond pulsars (MSPs), selected for their spindown power and proximity. From among these MSP, we have identified four which favor the presence of very…
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 Geminga pulsar has long been one of the most intriguing MeV-GeV gamma-ray point sources. We examine the implications of the recent Milagro detection of extended, multi-TeV gamma-ray emission from Geminga, finding that this reveals the…
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…
We report on the \textit{Fermi}-LAT observations of the Geminga pulsar, the second brightest non-variable GeV source in the $\gamma$-ray sky and the first example of a radio-quiet $\gamma$-ray pulsar. The observations cover one year, from…
TeV halos have been suggested as a common phenomenon associated with middle-aged pulsars. Based on our recent work on PSR~J0631+1036, which is the only known source positionally coincident with a hard TeV gamma-ray source and likely powers…
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…
Pulsars are observed to emit bright and spatially extended emission at multi-TeV energies. Although such "TeV halos" appear to be an approximately universal feature of middle-aged pulsars, there remains much to be understood about these…
Radio-quiet gamma-ray pulsars like Geminga may account for a number of the unidentified EGRET sources in the Galaxy. The number of Geminga-like pulsars is very sensitive to the geometry of both the gamma-ray and radio beams. Recent studies…
In recent years, the number of known sources emitting very- and ultra-high-energy gamma-rays has increased significantly thanks to facilities such as LHAASO and HAWC. Many of the observed sources are still unidentified or poorly constrained…