Related papers: High Energy Emission from Magnetars
The spectral characteristics of the pulsed gamma-ray emission from outer-magnetospheric particle accelerators are investigated. Either positrons or electrons are accelerated outwards by the magnetic-field-aligned electric field to emit…
In a strong magnetic field, B > 4x10^{12} G, gamma-rays emitted nearly along curved field lines adiabatically convert into bound electron-positron pairs (positronium atoms) rather that decaying into free pairs. This process may modify the…
A long BeppoSAX observation of the Galactic Center region shows that the spectrum of the diffuse X-ray emission from the SgrA Complex can be described with the sum of two thermal plasma models with temperatures of ~0.6 keV and \~8-9 keV.…
We present a hadronic model for gamma-ray production in the microquasar LS I $+61 303$. The system is formed by a neutron star that accretes matter from the dense and slow equatorial wind of the Be primary star. We calculate the gamma-ray…
The interaction between the magnetic fields of late-type stars and their close-by planets may produce stellar flares as observed in active binary systems. However, in spite of several claims, conclusive evidence is still lacking. We…
We investigate the $\gamma$-ray emission from a outer-gap accelerator, which is located in the outer-magnetosphere of a pulsar. The charge depletion from the Goldreich-Julian density causes a large electric field along the magnetic field…
Unsteady activity of gamma-ray burst sources leads to internal shocks in their emergent relativistic wind. We study the emission spectra from such shocks, assuming that they produce a power-law distribution of relativistic electrons and…
Highly magnetized neutron stars are a source of extreme transients observed in different bands, like the fast radio burst (FRB) and associated hard X-ray burst from the Galactic magnetar SGR 1935+2154. The origin of such outbursts, hard…
Until 2004, Anomalous X-ray Pulsars (AXPs) were known as strong emitters of soft X-rays only (< 10 keV). The discovery of hard X-ray component from AXPs provided important insight about their emission properties while it posed a serious…
We revisit the radiation mechanism of relativistic electrons in the stochastic magnetic field and apply it to the high-energy emissions of gamma-ray bursts (GRBs). We confirm that jitter radiation is a possible explanation for GRB prompt…
The observational properties of Soft Gamma Repeaters and Ano\-malous X-ray Pulsars (SGR/AXP) indicate to necessity of the energy source different from a rotational energy of a neutron star. The model, where the source of the energy is…
We present numerical simulations for energy spectra and angular distributions of nucleons above 10^{19} eV injected by the radio-galaxy Centaurus A at a distance 3.4 Mpc and propagating in extra-galactic magnetic fields in the sub-micro…
We study numerically the thermal emission of $e^+e^-$ pairs from a bare strange star heated by energy input onto its surface; heating starts at some moment, and is steady afterwards. The thermal luminosity in $e^+e^-$ pairs increases to…
Gamma-ray binaries, composed of a massive star and compact object, have been established as a new class of sources of very high energy (VHE) photons. The gamma-rays are produced by inverse Compton scattering of the stellar light by VHE…
Stellar flares have been extensively studied in soft X-rays (SXR) by basically every X-ray mission. Hard X-ray (HXR) emission from stellar superflares, however, have only been detected from a handful of objects over the past years. One very…
Context. More than one hundred GeV pulsars have been detected up to now by the LAT telescope on the Fermi gamma-ray observatory, showing peak energies around a few GeV. Current modelling proposes that the high energy emission comes from…
A principal candidate for quiescent non-thermal gamma-ray emission from magnetars is resonant inverse Compton scattering in the strong fields of their magnetospheres. This paper outlines expectations for such emission, formed from…
AXPs and SGRs constitute a special population of young neutron stars, which are thought to be magnetars, i.e., neutron stars with super-strong magnetic fields (10^14 - 10^15 G). Assuming that AXPs and SGRs accrete matter from a fallback…
We have obtained a firm detection of Cyg X-1 during its hard and intermediate spectral states in the energy range of 40 MeV--60 GeV based on observations by the Fermi Large Area Telescope, confirming the independent results at $\geq$60MeV…
Recent observations with the Imaging X-ray Polarimetry Explorer (IXPE) of two anomalous X-ray pulsars provided evidence that X-ray emission from magnetar sources is strongly polarized. Here we report on the joint IXPE and XMM-Newton…