Related papers: Gamma-rays from electrons accelerated by rotating …
There is solid observational evidence on the existence of massive, $M\sim 1~M_\odot$, highly magnetized white dwarfs (WDs) with surface magnetic fields up to $B\sim 10^9$ G. We show that, if in addition to these features, the star is fast…
Current gravitational wave detectors are sensitive to coalescing black holes and neutron stars. However, double white dwarfs (DWDs) have long been recognized as promising sources of gravitational waves, and upcoming detectors like LISA will…
The observed spectra of blazars, their intrinsic emission, and the underlying populations of radiating particles are intimately related. The use of these sources as probes of the extragalactic infrared background, a prospect propelled by…
Massive stars are mainly found in stellar associations. These massive star clusters occur in the heart of giant molecular clouds. The strong stellar wind activity in these objects generates large bubbles and induces collective effects that…
Many galaxy clusters have giant halos of non-thermal radio emission, indicating the presence of relativistic electrons in the clusters. Relativistic protons may also be accelerated by merger and/or accretion shocks in galaxy clusters. These…
The Fermi Gamma-Ray Space Telescope has discovered many gamma-ray pulsars, both as radio-loud objects and radio-quiet or radio-weak pulsars that have been identified through blind period searches. The latter presumably have gamma-ray beams…
Globular clusters (GCs) are emerging as a new class of gamma-ray emitters, thanks to the data obtained from the Fermi Gamma-ray Space Telescope. By now, eight GCs are known to emit gamma-rays at energies >100~MeV. Based on the stellar…
Some of the very high energy (VHE) gamma-ray sources detected with the modern generation of Cherenkov telescopes have been identified with previously known X-ray binary systems. These detections demonstrate the richness of non-thermal…
Gamma-ray observations of young star clusters have recently provided evidence for particle acceleration occurring at stellar wind termination shocks, fueled by the mechanical energy of stellar winds from massive stars. In this work, we…
Young massive star clusters (YMSCs) can produce gamma rays in the very-high-energy (VHE, E>100 GeV) range and have been proposed as sources that can accelerate cosmic rays up to PeV energies. Observations with current instruments have lead…
The repeating fast radio burst (FRB) localized to a globular cluster in M81 challenges our understanding of FRB models. In this Letter, we explore dynamical formation scenarios for objects in old globular clusters that may plausibly power…
GRBs are nowadays a rather well understood phenomenon in the soft (KeV-MeV) $\gamma$-ray energy band, while only a few GRBs have been observed at high photon energies ($E_{\gamma} \ut > 1$ GeV). It is also widely recognized that GRBs…
We study the gamma-ray emission from millisecond pulsars within the Milky Way's globular cluster system in order to measure the luminosity function of this source population. We find that these pulsars have a mean luminosity of $\langle…
Clusters of galaxies have not yet been detected at gamma-ray frequencies; however, the recently launched Fermi Gamma-ray Space Telescope, formerly known as GLAST, could provide the first detections in the near future. Clusters are expected…
Particle acceleration is expected to take place at shocks that form during the process of large scale structure formation. Electrons accelerated at such shocks can upscatter a small fraction of the photons in the cosmic microwave background…
We analyse 8 years of PASS 8 Fermi-LAT data, in the 60 MeV - 300 GeV energy range, from 30 high Galactic latitude globular clusters. Six of these globular clusters are detected with a TS > 25, with NGC 6254 being detected as gamma-ray…
The dominant mechanisms underlying high-energy $\gamma$-ray emission from galaxies vary by galaxy type. In starbursts, a major contribution comes from neutral pion decay. This is driven by interactions between interstellar gas and hadronic…
High-energy gamma rays are a valuable tool for studying particle acceleration and radiation in the magnetospheres of energetic pulsars. The six or more pulsars seen by CGRO/EGRET show that: the light curves usually have double-peak…
Gamma-ray binaries are orbital modulated gamma-ray sources in the Galaxy detected both at GeV and TeV energies. The high-energy radiation may come from the interaction of energetic electrons injected by a young pulsar and photons from the…
It is proposed that TeV gamma-rays and neutrinos can be produced by cosmic rays (CRs) through hadronic interactions in the innermost parts of the winds of massive O and B stars. Convection prevents low-energy particles from penetrating into…