The detection of extended very-high-energy (VHE, E > 0.1 TeV) gamma-ray emission surrounding the middle-aged pulsars Geminga and PSR B0656+14 by the HAWC Observatory in 2017 provided the first clear observational evidence for an extended inverse Compton component produced by electron-positron pairs diffusing away from pulsars, a component whose existence under conditions of suppressed diffusion had been anticipated theoretically. Such sources are now commonly referred to as TeV halos. These structures, now comprising two well-established halos and several candidates detected by HAWC, LHAASO, H.E.S.S., and Tibet ASγ, are understood to arise predominantly from inverse Compton (IC) scattering of interstellar radiation fields by relativistic electron-positron pairs that have escaped from their parent pulsar wind nebulae (PWNe) and diffuse through the surrounding interstellar medium (ISM). A defining observational characteristic of TeV halos is the strongly suppressed diffusion coefficient inferred within them, typically two orders of magnitude below the Galactic average, whose physical origin remains a subject of active debate. While purely leptonic models have been remarkably successful in reproducing the broadband spectral energy distributions and radial surface brightness profiles of known halos, the possible contribution of a hadronic component has also been discussed, particularly in light of LHAASO detections of ultra-high-energy (UHE, E > 100 TeV) emission from pulsar-associated sources. We show that, for middle-aged halo pulsars, the available pulsar potential and the rapid escape of energetic protons make a significant hadronic contribution unlikely, whereas PeV proton acceleration remains plausible in young, energetic pulsar wind nebulae. This review provides a comprehensive overview of the current observational landscape of TeV halos across the electromagnetic spectrum, from GeV energies probed by Fermi-LAT to the UHE domain accessed by LHAASO. We present the theoretical framework underpinning particle transport and emission in TeV halos, covering the standard two-zone diffusion model with isotropic and anisotropic diffusion scenarios, energy-dependent morphologies, and the role of self-generated turbulence. We critically examine the case for a lepto-hadronic interpretation, reviewing constraints from current gamma-ray and neutrino observations, including IceCube stacking analyses. We discuss the implications of TeV halos for the cosmic-ray positron excess measured by AMS-02 and DAMPE, the nature of particle escape from PWNe, and the transition from the nebular to the halo phase. Finally, we assess the transformative potential of next-generation observatories, the Cherenkov Telescope Array Observatory (CTAO), the Southern Wide-field Gamma-ray Observatory (SWGO), and upcoming neutrino telescopes, for resolving open questions through improved angular resolution, extended energy coverage, and Southern Hemisphere access to the inner Galaxy.
Electron Bernstein waves are electrostatic waves that play a fundamental role in wave-particle interactions, plasma heating,and energy transport in magnetized plasmas. Although the kinetic theory of EBWs has been extensively investigated under various plasma conditions, the influence of gravitationally induced drift on their nonlinear propagation has received comparatively little attention. In this work, we develop a nonlinear kinetic framework that self-consistently incorporates the gravitationally induced g⃗×B⃗ drift into the equilibrium electron dynamics and the dielectric response of EBWs in an inhomogeneous magnetized plasma. Starting from the Vlasov Poisson system, a modified equilibrium distribution function is formulated to account for both the equilibrium density gradient and the gravitational drift. A nonlinear dispersion relation is then derived within the plasma maser formalism by including the direct and polarization nonlinear coupling terms arising from low-frequency drift wave turbulence. To illustrate the influence of gravity on the reactive wave dispersion, numerical calculations are performed using the linear dielectric function. The results demonstrate that the gravitational drift systematically modifies the Bernstein-wave resonance condition through the K_⊥V⃗_⃗g⃗ term, producing perturbative shifts in the dielectric response and resonance frequencies. For the representative astrophysical plasma parameters considered in this study, these frequency shifts remain modest, consistent with the condition V⃗_⃗g⃗∥v_g . However, the derived kinetic formulation establishes the fundamental mechanism through which gravity influences EBW propagation and provides a general theoretical framework applicable to magnetized plasma environments where gravitational effects become comparatively more important. The present work therefore extends the conventional kinetic theory of EBWs by incorporating gravitationally induced drift effects within a unified nonlinear kinetic description.
We present an automated pipeline for detecting meteor trails in single-frame, half-minute-cadence all-sky images acquired by the Digital Autonomous Fireball Observatories (DAFO) network. Unlike existing approaches that rely either on handcrafted feature extraction or purely data-driven methods, the proposed system combines classical image processing techniques (Radon transformation and Fourier-transformation-based filtering) with a convolutional neural network (CNN) for robust classification of candidate trails. The method is specifically designed for fish-eye camera images and operates without dependence on a particular hardware configuration. It addresses limitations of our previous approach Suk and Šimberová [1], namely high false-positive rates and insufficient robustness to ambiguous trails such as blinking satellites and airplanes. The proposed pipeline was evaluated on data from eleven nights across multiple observatories. For clearly identifiable meteor events, the method achieves a precision of 93.9
Magnetic reconnection has recently emerged as an important process in the Martian space environment. In contrast to Earth, Mars lacks a global intrinsic dipole field and possesses an induced magnetosphere shaped by solar-wind interaction with the ionosphere, localized crustal magnetic anomalies, and abundant planetary heavy ions. Recent measurements from Mars Global Surveyor, Mars Express, MAVEN, and Tianwen-1 have revealed reconnection signatures in several distinct regions, including the dayside induced magnetosphere, the induced magnetotail, the crustal-field mini-magnetospheres, and the upper ionosphere. These reconnection signatures include Hall-like magnetic perturbations, multi-species ion outflows, magnetic flux ropes, reconnection fronts, and electron pitch-angle changes indicative of magnetic topology reconfiguration. This review synthesizes recent observational and theoretical progress on Martian magnetic reconnection and discusses its implications for magnetospheric structure, plasma energization, auroral activity, and atmospheric ion escape. Particular attention is given to the effects of interplanetary magnetic field variability, heavy-ion composition, and ionospheric collisionality, which distinguish reconnection at Mars from more familiar terrestrial cases. Although existing observations show that reconnection is a recurrent and potentially important component of Mars–solar-wind coupling, its global occurrence rate, spatial extent, and long-term atmospheric impact remain poorly constrained. Future coordinated multi-spacecraft measurements and multi-scale simulations will be critical for linking local reconnection physics to global plasma transport and atmospheric evolution.
The influence of the zonal harmonics J4 on the positions and stability of the out-of-plane equilibrium points of an infinitesimal mass, in the framework of the photogravitational elliptic restricted three-body problem (ER3BP), has been investigated. The positions change with an increase in the oblateness up to zonal harmonics J4, radiation pressure, eccentricity and semi-major axis of the orbit. The positions and stability of the out-of-plane points are affected by the parameters involved. The effect of these parameters on the positions of the out-of-plane equilibrium points is examined numerically both for the binary system 61 CYGNI and for arbitrary values. The results obtained from this study can be applied to different methods of celestial mechanics, with application to the planetary system.
